Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
gwez
←
Proto-Brythonic
*gwɨð
(inherited)
←
Proto-Celtic
*widus
(inherited)
→
English
Lostwithiel
(cognate)
→
Old English
wudu
(cognate)