Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
kalon
←
Proto-Brythonic
*kalon
(inherited)
←
Proto-Celtic
*kalonā
(inherited)
←
Welsh
calon
(cognate)
←
Cornish
colon
(cognate)
→
Welsh
calon
(cognate)