Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
gwreg
←
Proto-Brythonic
*gwrėg
(inherited)
←
Middle Breton
gruec
(inherited)
→
Breton
gwregel
(suffix)
→
Old Irish
frac
(cognate)