The Latin language left a considerable impression on British and its daughter languages. Principally, this influence came during the Roman Occupation (ad 55 – c.410) when parts of Britain were considerably Romanised. Although it could be said that Wales, Cornwall and the Cumbric Region were not as heavily Romanised as the south and east, the legacy of Roman Britain continued in these areas long after the legions had left. The language and culture of early medieval Britain was indellibly changed by contact with Rome and numerous words for new techonologies and objects entered British. The way medieval Brythonic languages were written shows direct continuity with the orthography of Romano-British writers.

The establishment and growth of Christianity from the fourth century brought a whole raft of words connected with the church and learning. As with many European languages, the process of borrowing from Latin continued indefinitely, with more complex words entering the language throughout the medieval and modern periods. The influence of French is also apparent in all the modern Brythonic languages, particularly Breton and Cornish. In some cases words were borrowed more than once, as with L. papyrus giving W. pabwyr and later papur.

The list below is not exhaustive, nor complete, but it gives an indication of the impact Latin had on the Brythonic languages and the kinds of words borrowed.

LatinMeaningBrittonic
abbāsabbotWB. abad, C. abas (from oblique)
abecedāriumalphabetW. (e)gwyddor, MW. agwyddawr (< Br. *abecēdārion), C. abecedari (late)
absentiaabsenceW. absen ‘slander, absence’
abstrūsusdeep, reservedW. astrus ‘complex’
addiscerelearn moreW. addysg ‘education’, addysgu ‘teach’, C. adhyski ‘educate’
admissus (equus)charging (horse}W. emys ‘warhorses, chargers’
adōrnāredecorateW. addurnu ’embellish’
aērairW. awyr, C. ayr, B. aer
aggregātiōgathering togetherMW. achreawdyr
altārealtarW. allor, C. alter, B. aoter
amplusgreat; abundantW. aml ‘many, large, ample, abundant’
anchoraanchorW. angor
angelusangelW. angel, C. el, B. ael
animalanimalW. anifail, C. eneval, B. aneval
antecēniumlunchW. ancwyn ‘dinner, supper; dessert’
ante tertiambefore threeW. anterth ‘height, prime’; C. androw, B. enderv ‘afternoon’
antigraphumtranscriptW. engraifft † (late)
antīquusancientOB. entic
apostolusapostleWB. apostol, C. abostel
aprilisAprilW. Ebrill, CB. Ebrel
arcabox, arkW. arch, C. argh, B. arc’h
archiepiscopusarchbishopW. archesgob, C. arghepskop, B. arc’heskob
armaarm, weaponW. arf, C. arv, B. arm (B. influenced by or borrowed from French)
ascendereascendW. esgyn, C. yskynna
asinusassW. asyn, C. asen, B. azen
astellasplinterW. astell ‘shelf, plank’
auctorauthorW. awdur, C. awtour, B. aozer (late and artificial, from oblique)
augustusAugustW. Awst, C. Est, B. Eost (< Br. *Āgustos)
aurumgoldW. aur, C. owr, B. aour
baculumstick, staffW. bagl ‘crook, crutch’
bāiulapail ?W. baeol ‘pail, pot’
baptīzārebaptiseW. bedydd ‘baptism’, C. bedidhia, B. badez
baptīzātusbaptizedW. bydysawd ‘Christendom’
barbabeardW. barf, CB. barv
benedīcerebless; praiseW. bendigedig ‘blessed’; C. benyga ‘bless’, B. bennigañ ‘bless’
benedictiōblessingW. bendith, C. bennath, B. bennozh
beneficiumbenefit, favourW. benthyg ‘loan’
bēstiabeastW. bwyst
BibliaBibleW. Beibl, C. Beybel, B. Bibl (all late)
bovīnuspertaining to cowsC. bewin, B. bevin ‘beef’
bracchiumarm, branchW. braich, C. bregh, B. brec’h
brassicacabbageW. bresych ‘cabbages’
būbalusbuffaloW. bual †, CB. bual
buccacheekWC. boch, B. boc’h
caballushorseW. cefyll, C. cevil
cæsellumchisel(VL. cisellum)
calamusstalk, reedC. kala ‘straw’, B. kolo ‘straw’
calendæCalendsW. calan, CB. kalan (< VL. Kaland-)
calidāriacooking potW. callor †, C. kawdarn (from French) ‘cauldron’, B. kaoter
calix, calic-wine cupW. caregl C. celegel ‘chalice’
callidusskilful, cleverW. call ‘wise’, C. kall ‘cunning’
calx, calc-lime, chalkW. calch, C. kalgh ‘lime’, B. kalc’h
camisiashirt, tunicC. hevis ‘blouse’, B. hiviz (poss. via French or Old English)
campusplain, sports fieldW. camp ‘game, feat’, campwr ‘athlete’; C. campier ‘champion’, B. kamp ‘feat’
cancellāriuschancellorW. canghellor, B. kañeller
candēlacandleW. cannwyl, C. kantol, B. kantoel (< Br. *cantēlā)
capistrumhalterW. cebystr ‘halter, tether’
capitulumchapterW. cabidwl
captīvitāscaptivityW. caethiwed
captīvuscaptiveW. ceithiw ‘captivity; enslaved’
carcerprisonW. carchar; C. karhar ‘fetter, shackle’, B. karc’har
carēnumsweet wineW. cerwyn ‘vat, tun; wine-press’
cāritāsdearness; affectionW. cardod ‘charity’, B. karitez
carptuspluckedW. carth ‘offscouring’, carthen ‘coarse cloth’, carthu ‘cleanse’; C. karth ‘cleansing’, B. karzh ‘cleaning’
cāseuscheeseW. caws, C. keus, B. keuz
castaneachestnut (tree)W. castan, C. kesten, B. kistin
castellumcastleW. castell, C. kastel, B. kastell
castīgārepunish, reproveW. castwyo ‘chastise’
castrumfort, campW. caer ‘fort’ (either a very early loan from Latin or a native word)
casulavestment 
catēnachain, fetterW. cadwyn
cathedrachairW. cadair, CB. kador
cattacatW. cath
caucusdrinking vesselW. cawg ‘bowl’ (Jackson says this is not a Latin loan)
cauliscabbageW. cawl ‘broth’; C. kowl ‘broth; cabbage, kale’, B. kaol
cavellalittle caveW. cawell, C. kowel ‘basket’, B. kavell
cavitāscavityW. ceudod (from oblique)
cavushollow; cavityW. cau, C. kowva ‘cavity’, kow ‘hollow’, B. kev ‘cavity’
cellacell, stallW. cell, CB. kell
cēnadinnerW. cwyn ‘meal’, cinio, MC. kynyow, C. kinnyow, B. koaniañ
centrumnailW. cethr †, C. kenter
cērawaxW. cwyr, C. kor, B. koar
certusfixed, determinedW. certh ‘awful, intense, keen’, B. kerzh ‘certainly’
ChristiānusChristianW. Cristion
ChristusChristW. Crist
cingulabelt, girdleW. cengl ‘girth, girdle’
cippusstake; gravestoneW. cyff ‘stock, chest’; C. kyf ‘log’, B. kef
circuluscircleOW. circhl, B. kerl
cistabasket; chestW. cest ‘belly, basket, hold’, cist ‘chest, box’ (the latter < ON. kista)
civitās communityW. ciwed ‘rabble’, ciwdod † ‘people, race’, B. keoded ‘city’
classisgroup, classW. clas ‘cloister’, B. klas ‘class’
clēricusclergyman, clerkOC. cloireg, C. klorek,B. kloarek, OI clérech
clērusclergyW. cloer MW. clwyr. B. kloer pl of kloarek
cloccabellW. cloch, C. klogh, B. kloc’h (this may be a Celtic word borrowed into Latin)
*cloppuslameW. cloff, C. klof, kloppek (cf. Fr. éclopé)
coāgulumrennetW. caul; ceulo, C. kowla ‘curdle’, B. kaoul
coctuswell-consideredW. coeth ‘pure, fine, excellent’
columbadove, pigeonW. colomen, C. kolom ‘pigeon’, B. koulm, kolom ‘dove’
columnacolumnW. colofn, C. koloven, B. kolonenn
commendāreentrust, commitW. cymynnwr ‘testator’; C. komendya ‘introduce, recommend, approve’
compārspouse; equalW. cymar ‘partner, mate’ (from oblique), B. kempar; C. kespar ‘mate’, B. ketpar
comparārecompare; matchW. cymharu ‘compare’, C. komparya (late)
compelleredrive, compelW. cymell, C. kompella (late)
*concausacauseW. cyngaws † ‘lawsuit’
condīcereagree on, promiseW. cynnig ‘attempt; offer’, C. kynnik ‘offer’, B. kinnig ‘offer’
cōnfectiōmaking; confectionW. cyffaith, C. kyfeyth ‘confection’
cōnfessiōconfessionW. cyffes, B. kofesion
congregātiōunion, societyW. cyngreawdr
congressusmeeting, unionW. cyngres ‘congress’
cōnsecrāreconsecrateW. cysegru
cōnsiliumcouncilW. cusyll † ‘advice’, C. kussul ‘council; counsel, advice’, konsel ‘council’ (late), B. kuzul ‘council; advice’
cōnstruendaconnectingW. cystrawen ‘syntax, construction’
contrāriusoppositeW. cythrawl ‘devil’
coquīnakitchenW. cegin, CB. kegin (< Br. *cocīnā)
coquus, coquerecookW. cog, cogi, C. kog, kegi
corpusbodyW. corff, CB. korf
corōnacrownW. corun ‘crown (anat.)’, coron, C. kurun, B. kurunenn
corrigiashoelaceOW. corruui, W. carrai, MB. coreenn
coxahipW. coes (may be cognate, cf. G. cas ‘foot’)
creātorcreatorW. creawdwr (from oblique), C. kreador, B. krouer
creātūracreatureW. creadur, C. kreatur, B. krouadur
crux, cruc-cross, gallowsW. croes, crog, C. krowskrogbren ‘gallows’, B. kroaz
cubiculumbedroomW. cuddygl, cufygl † cubicle’
cubitumelbow; cubitW. cufydd ‘cubit’
cucullushood, cowlW. cwcwll, C. kugol
culcitamattress, pillowW. cylched †, C. kolhes ‘quilt’ B. golc’hed
cultellussmall knifeW. cyllell, C. kollel, B. kountell, kontell
culterknife, razorW. cwlltr ‘coulter’
cumulusheap, massW. cwmwl, C. komolen, B. koumoul ‘cloud’
cuneuswedgeW. cŷn ‘chisel’
cunīculusrabbitW. cwningen, C. konin, B. konifl, konikl (late, prob via English < French)
cūpavat, tunW. cib ‘pod, husk’, B. kib ‘cup’
cupiduslustful, greedyW. cybydd ‘miser’
cūracare, trouble, anxietyW. cur ‘anxiety; ache’; CB. kur ‘cure’
decimārepay tithesC. degevi
decimus, decumustitheW. degwm, C. dega, B. deog
defectusweak, failingW. diffaith ‘waste, barren’, C. difeyth ‘waste’
dēfenderedefend, repelW. diffynnydd, C. difenner ‘defendant’, B. difenn ‘defend’
dēficerefail; be lackingW. diffyg ‘lack’;C. difygya
dēfinīredefine, limitW. diffinio, B. difin ‘result’
dēlēreannihilate; blot outW. dileu, C. dilea ‘delete’
dēnāriussilver coinC. diner ‘penny’; B. diner ‘denarius’
dēnsusthick, denseW. dwys, C. doos, B. doues
dēpenderedependW. dibynnu
dēscenderedescendW. disgyn, C. diskynna, B. diskenn
dēsertumdesert, wastelandW. diserth †, B. dezerzh
dēspectusdespisedC. dyspyth, despit (poss. late)
dēstillāredrop down, distilW. distyll, distyllu ‘distil’
dēstrueredemolish, destroyW. distryw ‘destruction’, C. distrui ‘destroy’, B. distrujañ
dēsubitōall of a suddenW. disyfyd ‘sudden’
diabolusdevilW. diawl, diafol, C. jowl, B. diaoul
diāconusdeaconW. diacon, OC. diagon, B. diagon
dīluviumflood, delugeW. dilyw, C. dial
dīmidiumhalfW. dimai, C. demma ‘half-penny’ (late, perhaps from French demi)
discerelearnW. dysgu, C. dyski, B. deskiñ
discipuluspupil, discipleW. disgybl, C. dyskybel, B. diskibl
diurnātaday, daytaleW. diwrnod
dīvīnussoothsayerW. dewin, B. deviñdewiñ
dīvisusdivisionWC. dewis ‘choice’B. diuz
doctorteacherW. doethor, doethur ‘doctor, teacher’
doctuslearned, skilledW. doeth
dolor, dolōr-sorrow, painW. dolur (from oblique), C. dolor
dolōrōsuspainful, sorrowfulW. dolurus
dracōdragonW. draig, CB. dragon
dūrushard, toughWC. dur ‘steel’, B. dir ‘steel’
ecclēsiachurchW. eglwys, C. eglos, B. iliz (< Br. *eclēsjā)
Eleēmosynaalms, almshouseW. elusen ‘alms’
elementumelementW. elfen, C. elven, B. elvenn
episcopusbishopW. esgob, C. epskop, B. ekob
ēvangeliumGospelW. efengyl, C. aweyl, B. aviel
excommuniōexcommunicateW. esgymun, ysgymun, C. emskemuna, B. eskumunugañ
excūsāreexcuse, apologise forW. esgus, C. askus, askusya, B. iskuz, iskuziñ
execūtuspursued; executedW. esgud ‘active, quick’, C. uskis ‘fast, rapid’, B. eskuit ‘prompt’
exiguitassmallnessMW. eissywet ‘lack, want’
exiguussmall, meagreW. eisiau ‘want’
exorīrī, exortusrise, arise; risenC. sordya ‘arise; raised’
extendereextend, stretch outW. estyn, C. ystyn ‘reach, extend’, B. astenn
extrāneusstrangerW. estron, CB. estren
fababeanW. ffeuen, ffa, C. faven, B. fav, faw
factusmadeW. ffaeth †’cultivated’, C. feyth ‘fertile’
faculalittle torchW. ffagl ‘torch, flame’, C. faglen ‘torch’
fāgusbeechW. ffawydden, C. fawen, B. fav, faou
falsusfalseW. ffals, B. faos
fascisbundle, faggotW. ffasg
februāriusFebruaryW. Chwefror, C. Hwevrer, -l, B. C’hwevrer
fenestrawindowW. ffenestr, C. fenester, B. fenestr
feniculumfennelW. ffenigl, C. fenogel
fēnum, fænumhayC. foon ‘new-mown hay’, B. foenn ‘hay’
ferrāriusblacksmithC. ferror
festīnārehurry, make hasteC. fistena
fībulaclasp, broochW. hual, C. fu ‘fetter, shackle’, B. hual
fidēsfaith, trustW. ffydd, C. fydh, B. feiz, fez
fīnisboundary, limitW. ffin, CB. fin
firmāmentumsupportW. ffurfafen ‘firmament, sky’; C. firmament, B. firmanant (late)
firmusstable; powerfulW. ffyrf, C. fyrv, B. ferv
flagellumwhipW. frewyll
flagrāreblaze, burnW. fflerio ‘flare’; perhaps C. flerya ‘smell, stink’, B. flaeriañ ‘stink’
flammaflameW. fflam, CB. flamm
focushearth, fireplaceC. fog ‘focus, furnace, hearth’
fontānafountain, springW. ffynnon, C. fenten, B. feuteun
fōrmaform, shapeW. ffurf, C. furv
fossaditch, trenchW. ffos, B. foz; C. fos ‘wall’
foveapitW. ffau, C. fow, B. fav ‘den, lair’ (< Br. *fowjā)
frēnumbridleW. ffrwyn, C. fruyn (*froon)
fructusfruitW. ffrwyth, C. frooth, B. frouezh
fūcusdeceitW. ffug, C. fug ‘counterfeit, fake; fictitious’
fugaflight, escapeW. ffo, C. fo, B. fu
fūnisrope, cordW. ffun
fūrthief 
furcaforkW. ffwrch, C. forgh, B. forc’h
furnusovenW. ffwrn, C. forn, B. forn, fourn
fūstisstick, club, cudgelW. ffust ‘flail’, C. fust ‘club, cudgel’, B. fust ‘handle’
gemellustwinW. gefell, C. gevel, B. gevell
gemmagem, jewelW. gem
glūtenglueWB. glud, C. glus
gradusstep, degreeW. gradd, C. gradh
grammaticagrammarWB. gramadeg, C. gramasek
graphiumstylus; pencilW. graiff(t) ‘pen, pencil’
grātiagrace, favourWCB. gras (prob. from ME or OF grace)
grex, greg-flock, herd; troopWCB. gre
habēnastrap, reinsW. awen, MW. afwyn
hanaperiumlarge vaseC. hanaf ‘drinking cup’ (prob from French hanap ‘goblet’)
historiahistory; inquiryW. ystyr, C. styr ‘meaning’
honestushonored, respectableW. (g)onest, CB. onest
hōrahourW. awr, C. our, B. eur
hospeshost, visitor, friend, strangerW. osb ‘guest, lodger; stranger’
hospitiumhospitality; lodgingW. ysbyty, B. ospital
humilishumble, lowlyW. ufyll †, CB. uvel
iānuārius JanuaryW. Ionawr; CB. Genver (via French)
imāgō, imagin-likeness, imageC. aven
imperātoremperorW. ymerawdwr, ymherodr (from oblique); C. emperour, B. ampereur, impalaer (via French or English)
incēnsumincenseC. encois, B. ezañ(s)
increpitusrebukedMW. anghreith
indulgensindulgent, kindW. annwyl ‘dear’ (? < Br. *induglens)
infernahellW. uffern, C. yfarn, B. ifern
initiumbeginning; ShrovetideW. Ynyd, C. Enes, B. Ened
iovisJupiterW. Iau, C. Yow, B. Yaou
iugumyokeW. iau, C. yew, B. yev (may be cognate)
iusculumsoupW. isgell, OC. iskel
laborlabour; workW. llafur, C. lavur (from oblique)
labōriōsusdifficult; industriousW. llafurus, MW. llafuryus; C. lavurys ‘worn out’
lāicuslay, unconsecratedW. lleyg, C. leg
lāminaplate, bladeW. llafn, C. lown, B. lavn, laon
larguscopious; liberalMW. llary ‘generous’, W. llariaidd ‘meek’
latexwater, liquidC. las ‘liquor’
LatīnaLatinW. Lladin
latrōmercenary; brigandW. lleidr, C. lader, B. lâer ‘thief’
laus, laud-praiseW. llawdd 
laurusbay treeW. llawrwydden, llawryf, B. lore
laxuswide; loose; freeW. llaes, C. lows, B. ? loask
lectīcalitter, sedanW. lleithig
lēctiōreadingW. llith ‘lesson’
lēgālislegal, lawfulC. lel ‘loyal, trusty, genuine’ B. leal ‘loyal’ (perh. from OF. leal)
legendusa thing to be readW. llên, C. lien, B. lenn ‘literature’
legereread, reciteW. lleu ‘read’
legiōnēslegionsW. lleon, lleion
leōlionW. llew, C. lew
liberbookW. llyfr, C. lyver
lignumwood, firewoodW. llwyn ‘grove, bush’ (may be native)
līneathread, lineW. llin, llinell, llinyn ‘line’
līnumflax; linenW. llin ‘flax, linen’
litteraletterW. llythyr, C. lyther, B. lizher
lixiviumlyeOW. lissiu, W. lleisw, OB. lisiu, B. lisiou
locārelease, hire out; investW. llog ‘interest’, llogi ‘hire’
loculuslittle placeC. logel ‘coffin’
longa nāviswarshipW. llong (some argue that this is a native word)
lucernalampW. llusern (prob from OF lucerne or ML); C. lugarn; B. lugern ‘brilliant’
lūnamoonW. Llun, CB. Lun
lōrīcabreasplateW. llurig
māceriawallW. magwyr, B. moger, magoar; C. magor ‘ruin’ (< L. macēria)
maculaspot, stain
mesh
MW. [m]aglei ‘stained’, B. magl ‘lozenge’
W. magl ‘snare’, C. maglen ‘trap’
magistermasterW. meister, C. mester, B. mestr
māiorelderWB. maer, C. mer ‘mayor’
maiusMayW. Mai, C. Me, B. Mae
maledīcereslander; curseW. melltigo ‘curse, slander’
maledictumcurseW. melltith, C. molleth
malignusunkind, ill-naturedW. malen ‘evil, cursed’, MW. malaen; C. malan ‘devil’
manicæglovesWB. maneg, C. manek
mantēllumcloakWB. mantell, C. mantel
manūbriumhandleW. mynybr † ‘hilt, handle’
margarītapearlW. mererid 
Mars, mart-MarsW. Mawrth, C. Meurth, B. Meurzh
martyrmartyrW. merthyr, C. merther, B. merzher
martyriummartyr’s graveW. merthyr ‘sanctified cemetary’
mātūtīnummorning, earlyW. ers meitin ‘a good while since’; C. myttin
medicusdoctorW. meddyg, C. medhek, B. mezeg
memoriamemory, remembranceW. myfyr ‘meditation’
mēnsatable; courseW. mwys C. moos
mēnsūrameasure(ment)W. mesur, C. musur, B. muzul, muzur (< L. mēsūra)
mercātusmarket, fair; tradeW. marchnad, C. marhas, B. marc’had
mercuriusMercuryW. Mercher, C. Merher, B. Merc’her
mīlessoldierW. milwr
mīlitārismilitary; soldierW. miledawr ‘host, warband, army’
mīlle, mīliathousand; mile(s)WCB. mil (from the plural), W. milltir, C. mildir, B. miltir (from singular)
ministerservant, attendantC. menyster, B. ministr ‘minister’
mīranduswonderfulW. mirain ‘comely’
mīrārīwonder, be surprisedC. mires ‘look, see, behold’
modusway, methodW. modd
molīnamillWCB. melin
monachusmonkW. mynach, C. managh, B. manac’h
monumentummemorialW. mynwent ‘graveyard’ (from plural)
mūlusmuleW. mul
mūruswallWB. mur
mūsculusmouse; muscleW. misglen, C. mesklen, B. meskl ‘mussel’
mūtārechange, exchangeW. mudo ‘move, emigrate’
mūtusdumb, muteWB. mud
myrrhmyrrhW. myrr, C. mer, B. mirr
nātālīciaChristmasW. Nadolig, C. Nadelik
nātūranatureWCB. natur (late)
nebulamist, vapour, cloudWC. niwl
nōnaninth hourW. nawn
notanote, markW. nod, C. nos
numerusnumberW. nifer, C. niver
nuptiāliawedding feastW. neithior
occāsiōopportunityW. achos ’cause’, C. acheson ‘motive, reason’
occlūdereshut up, stopW. machlud ‘set’
occupāreseize, occupyW. achub ‘save’
ōceanusoceanW. eigion
ōdaodeW. awdl, C. od (all late)
offerendusthing to be offeredW. offeren ‘mass’, C. oferen
oleumoilWC. olew
operaworkC. ober
ōrātiōspeech; orationW. arawd;MB. euret ‘marriage’
ōrātorspeakerW. arawdr
ōrdōline, order, rankW. urdd ‘order, rank’, C. urdh ‘order’, B. urzh ‘order’
organumorgan, instrumentWC. organ
orthographiaorthographyW. orgraff (late)
ostreaoyster, mussel 
pænitēreregret, be sorryW. penyd ‘penance’, C. penys ‘do penance’
pāguscountry, districtW. pau, C. pow
palātiumpalaceW. palas, plas, C. palys (from or influenced by ML or OF palais)
palla, palliumrobe; cloakC. pall ‘mantle’
palmapalmW. palf, C. palv
pannuspiece of clothW. pannu ‘full’, C. pan ‘cloth’
pāpapopeWCB. pab
papāverpoppyW. pabi (probably influenced by Eng. poppy)
pāpiliōbutterflyW. pabell ‘tent’ (< Br. papiliō. The W. singular is a back-formation from pebyll, assumed to be a plural)
papyruspapyrus, paperW. pabwyr ‘rushes’; papur, C. paper ‘paper’ (late)
pār, par-equal, like; partnerW. pâr ‘pair’, C. par ‘equal’; W parhau ‘continue’ (< Br. *paros agame)
parabolacomparison; parableW. parabl ‘speech’; C. parabyl, parabolen ‘parable’
paradīsuspark; paradiseW. paradwys (< L. *paradēsus), C. paradhis
parātusready; equippedW. parod, paratoi ‘prepare’, C. pareusi ‘prepare’
pariēs, pariet-wallW. pared (< Br. *paretem), parwydydd, C. paros
pars, part-part, shareWC. parth
pascerefeed, put to grazeW. pasgedig ‘fatted’
PaschaEasterW. Pasg, C. Pask
pastinacaparsnipW. panasen, C. panesen (by metathesis)
patellasmall dish, plateW. padell, C. padel
pater nosterour fatherWC. Pader
pāvōpeacockW. paun, C. payon
pāx, pāc-[kiss of] peaceW. pocio ‘to kiss’, pacs ‘kiss of peace’ (late), B. pok ‘kiss’
peccātorsinnerW. pechadur, C. pehador (from oblique)
peccātummistake, sinW. pechod, C. pehes
pedālisa foot longW. pedol ‘horseshoe’
pedesterpedestrianW. peddest ‘pedestrian, footman; foot soldier’
pedes, pedit-walker, foot soldierW. peddyd ‘foot soldier, pedestrian’
penna, pinnafeather; penW. pin ‘pen, stylus’
pēnsumweightW. pwys, C. poos (< VL. pēsum)
pentecostPentecostC. Penkost (probably late or learned)
peregrīnusforeignerW. pererin, C. perherin ‘pilgrim’ (< Br. *pergerīnos)
perfectuscomplete, perfectW. perffaith, C. perfydh
perīclumdanger, riskW. perigl, C. peryl (influenced by OF peril)
per mediusthrough the middleW. perfedd ‘entrails’, C. pervedh ‘interior’
persōnapersonWC. person
pertinēreconcern; belongW. perthyn
petereseek, look for, demandC. pesi ‘pray’
pexa (tunica)carded (tunic)W. pais ‘petticoat’, C. pows ‘dress, frock’
phialasaucerW. ffiol ‘vial, bowl’, C. fiol † ‘cup’
pilaballW. pêl, C. pel
pīnuspineW. pîn, C. pin
pīpapipeW. pibellpib, C. pibel, pib
piperpepperW. pupur, pybyr, C. puber (probably late, perhaps influenced by Eng.; ‹u› is due to the adjacent labials, cf.W. pump < pymp).
pirum, piruspear (tree)WC. peren (from VL. *pera)
pisa, pisumpeaW. pysen, C. pesen
piscātorfishermanW. pysgodwr, pysgotwr, C. pyskador
piscis, piscātusfishW. pysgod, pysg, C. pysk
pix, pic-pitchWC. pyg
placituspleasing; principleW. oblegid ‘because’, C. plegadow ‘pleasing’
plāgablow, wound; plagueWC. pla
plantashoot, slip; soleW. planhigyn, C. plans ‘plant’
plēbscommon peopleW. plwyf, C. pluw ‘parish’
plectereplait, braidWC. pleth ‘plait’ (n.)
plicitumfoldedW. plith ‘midst’ (< Br. plict-) ?
plicārefoldW. plygu, C. plegya
plūmasoft featherW. pluen, C. pluven
plumbumleadW. plwm, C. plomm
pœnapenalty, punishmentW. poen, C. pon, payn (latter from OF peine)
pollenfine flourW. paill ‘flour, pollen’
pondus, ponder-weight, burdenW. pwnn, pynner, B. pounner ‘heavy’
pons, pont-bridgeW. pont, C. pons
populuspeople, nationW. pobl, C. pobel (< Br. *poplos)
porcelluslittle pigW. porchell, C. porhel
porrumleekC. poren
portagate; entrance, exitW. porth ‘door’ (m.), C. porth ‘gate’ (m.)
portārecarry, conveyW. porth ‘support, help’ (may be native)
portusharbour, port; havenW. porth (f.), C. porth (m.)
postilēnacrupperW. postolwyn, pystolwyn
postispostWC. post
præbendāriusprebendaryC. pronter ‘priest’
præceptamaximW. pregeth, C. pregoth ‘‘sermon’
prædicāreproclaim, praiseC. predheges ‘rant’
prædiumestateW. praidd ‘flock’, B. preiz
præsæpestable, stall, fold; cribW. preseb ‘manger, crib’, C. presep ‘manger’, B. prezeb ‘manger’
præsēns, præsent-presentW. presen, C. present
prandiumlate breakfast; mealW. prain ‘feast, banquet’
prātummeadow, grassC. pras
presbyterelderW. pryfder ‘priest’
pretiumprice, value; rewardWC. pris (probably from OF pris)
prīmusfirst, foremostW. prif
prīvātusindividual, privateW. priod ‘own; spouse’, C. pries ‘married; spouse’
probāreprove, showW. profi, C. previ
prophētaprophet, soothsayerW. proffwyd, C. profet
psalmuspsalmWC. salm (late)
psaltēriumpsaltery; song; the PsalmsW. sallwyr ‘Psalter, Book of Psalms’
pugillāreswriting tabletsMW. peullawr, OW. poullaur
pullicantiōcock-crownW. plygain, pylgain ‘dawn’
pulvis, pulver-dust, powderW. pylor ‘powder’, perhaps C. pilm ‘flying dust like flour’
pūnctumpoint, dot; piercedW. pwyth ‘stitch’
purpurapurpleW. porffor, C. purpur
pūrusclear, pureWC. pur
pūs, pūr-pusC. purek ‘snotty’
puteuswell, pitW. pydew
putridusrotten, decayedW. pudr, C. poder
quadrāgēsimaLentW. carawys, g-, C. Korawys
quadrellum B. coazrel ?
quæstiōseeking, investigationW. gorchest ‘feat, excellence’
quartāriusquarter-pintW. chwarthor
rapere, rapi-seize, plunderW. rhaib ‘greed’
rasculus W. rhasgl ‘type of knife’
rēgālisroyalC. ryal (probably from Br. *rigālos)
registrumregisterW. rhestr
rēgularuleW. rheol, C. rewl
rēliquiæremainder; relicsW. rhelyw ‘remainder’
rēmusoarW. rhwyf, C. rev
rētenet; snareW. rhwyd, C. roos
rosaroseW. rhosyn, C. rosen
ruīnacollapse; ruinsW. rhewin
saccusbag, purseW. sach, C. sagh
sacrāmentumlegal depositW. sagrafen ‘sacrament’
sacrificiumsacrificeW. segrffyg ‘Eucharist, Holy Communion’
sagittaarrowW. saeth, C. seth
salsīciasausageW. selsig
sanctussacred, holyW. sant, C. sans
saturnusSaturnW. Sadwrn, C. Sadorn
scabillum, scamellumstoolW. ysgafell ‘ledge’, C. skavel ‘stool’
scālæsteps, ladderW. ysgawl, C. skeul
scholaschool; sectW. ysgol, C. skol
scientiaknowledgeC. skians
scōpæ, scōpāriumbroomW. ysgub, ysgubor; C. skubel
scrībendusthing to be writtenW. ysgrifen
scrīberewriteW. ysgrifo, C. skrifa
scrīniumbook boxW. ysgrîn ‘shrine’
scrīptūrawriting, documentW. ysgrythur ‘scripture’
scutellabowlC. skudel
sēbumtallow, greaseW. swyf 
secāleryeC. sugal
sēcūrusuntroubled, carefreeW. segur, C. syger ‘idle’.  W. sicr ‘sure’  is a late borrowing of the same word, existing alongside siŵr, C. sur < ME sur)
sēdesseat, chairW. swydd, C. soodh ‘office, job’
sentīrefeel, see; experienceW. synnwyr ‘sense’, synnu ‘wonder’
septimānaweekC. seythen, B. sizun; OI sechtman, G. seachduin
sēricasilkW. sirig, serig
sērōlateW. hwyr ‘evening, late’
serpēnsserpent, snakeW. sarff, C. sarf
serptus(steep)WC. serth
serrasawW. ser ‘sickle, scythe, billhook’
sextāriuspintOW hestaur, MW. hestawr
siccitāsdryness, droughtW. syched, C. sehes ‘thirst’
siccusdry; thirstyW. sych, C. sygh
signummark, sign; sealW. swyn ‘charm, magic’, C. soon ‘blessing’
sisterestop, check; standC. cessya
sōlsunWC. Sul
solidussolid; gold coinW. swllt, C. sols ‘shilling’
solumground, floor, bottomW. sail, C. sel ‘base, foundation’ (< Br. *soljā VL. solea)
sonussound, noiseW. sŵn ‘noise’, sôn ‘mention, rumour’, C. son ‘sound’
spatiumspace, roomW. ysbaid (of time), C. spas (prob from ME < OF espace)
spīritusspiritW. ysbryd, C. spyrys
splendērebe brightC. splanna
splendidusbright, clearW. ysblennydd, C. splann
splendor, splendōr-brightness, clarityW. ysblander, C. splander ‘gloss, polish’ (either from the nominitive with the native ending -der ‘-ness’ or from the adjective)
spoliumspoils, bootyW. ysbail
spongiaspongeW. ysbwng, C. spong (< Br. *spongos)
stabulumstall, stable; cottageW. ystafell, C. stevel ‘room’
stagnumtinW. ystaen (not in GPC)C. sten
stāmenwarp, threadW. ystof ‘warp’, C. steuv, B. steuñv
stēllastarW. Ystwyll, C. Stul ‘Epiphany’
sterneresaddleW. ystarn
stimulusgoadW. swmbwl
stipulastubbleW. sofl, C. sowl
storāxresinW. ystor ‘resin’
stragulacovering, tapestryC. strel ‘mat, rug’
strātūra(saddle)W. ystrodur
strigilisscraper, strigilOC. streil ‘strigil’ (< L. strigla)
structūrastructureC. strethur
struereplace together; arrange; buildW. ystryw ‘ruse, trick; ability, skill’
superbusarrogant, overbearingW. syberw ‘sober, mannerly’
syllabasyllableW. sillaf, C. sylaben
synodussynod, meetingW. senedd, C. senedh ‘parliament’
tabellasmall boardW. tafell ‘slice’,
tabernainnW. tafarn, C. tavern
tabulaboard, plank; tableW. taflen ‘list’, tafl, tafol ‘scales’
tabulātumfloor, storeyW. taflod ‘loft’
tēgacoverW. twyg †’gown’
tēlaweb; planW. twyll ‘deceit’C. toll
temperāretemper, moderateW. tymer ‘temper’ (sense development is late); C. tempra ‘moderate’
tempestāsweather, stormW. tymestl
templumsanctuary, templeW. teml, C. tempel, templa
tempus, tempor-time; tenseW. tymp, tymor ‘season’
tenertender, delicate; weakW. tyner, C. tender (from of influenced by OF tendre)
terminusboundary-line, limitW. terfyn
tertiānafeverC. terthen
testimōniumevidence, testimonyW. testun ‘text’, C. dustuni ‘testimony’
testiswitnessW. tyst, C. desta
thronusthroneC. tron
tonustone, soundW. tôn, C. ton
tortaflat cake; loaf of breadWC. torth
tractātushandlingW. traethod ‘treatise’
trānstrumthwartW. trawst ‘beam’, C. treuster
trīnitāstrinityW. trined, trindod, C. trindas
tripēs, triped-three-leggedC. tribet ‘andiron’ (may be from ME. trefet ‘trivet’)
tristissad, melancholyWC. trist (< Br. *trīstis)
tructatroutC. truth (< VL. *trutta)
trullaladle, scoop; wash-basinW. trull ‘wine vessel, cup’, trullio ‘pour or serve (drink)’ (uncertain, perhaps a late borrowing)
turbadisorder, riot;
troop, crowd
W. twrf ‘noise, tumult’, C. tervans ‘tumult, turmoil’W. torf ‘crowd’
turristowerW. twr ‘heap’; W. tŵr, C. tour ‘tower’ (from or influenced by ME tour < OF tur)
tūs, thūsincenseW. thus
unguentumointment, perfumeW. ennaint, C. unyent
ūnitāsonenessW. uned, C. unses ‘unit’
ursusbearC. ors
vāgīnasheath, scabbardW. gwain, OC. guein, C. gon †
vēlumsail, curtainC. gool, B. gouel
vēnātorhunterB. gwinaer
venēnumdrug, potion; poisonW. gwenwyn, C. gwenon
venus, vener-VenusWC. Gwener
versusline, row; verseWC. gwers
vēsīcabladder, purseW. chwyssigen, C. gusigan, gysigan † (< L. vesīca)
vespereveningW. gosber, C. gwesper ‘vespers’
vīcusvillage, estateW. gwig ‘wood’; C. gwig ‘village’, gwikor ‘merchant’
vigiliawatch; vigilW. gwyl, C. gool ‘feast, holiday’
vīnumwineWC. gwin
vīperaviperW. gwiber
virginitāsvirginityW. gweryndod
virgōmaid, virgin; girlW. gwyry, C. gwyrgh
viridisgreen, freshW. gwyrdd, C. gwyrdh (may be cognate)
virtūsvalour, virtue, worthW. gwyrth ‘miracle’
vitrumglassW. gwydr, C. gweder
vīverraferretW. gwiwer ‘squirrel’