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