Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
karout
←
Proto-Celtic
*kareti
(inherited)
←
Welsh
caru
(cognate)
←
Proto-Indo-European
*keh₂-
(derived)
←
Cornish
kara
(cognate)
←
Middle Breton
carat
(inherited)
→
Cornish
kara
(cognate)