Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
mab
←
Proto-Brythonic
*mab
(inherited)
←
Proto-Celtic
*makʷos
(inherited)
→
Breton
mibien
(suffix)
→
Breton
lezvab
(prefix)
→
Cornish
map
(cognate)