Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
dall
←
Proto-Brythonic
*dall
(inherited)
←
Proto-Celtic
*dallos
(inherited)
→
Breton
logod-dall
(compound)
→
Welsh
dall
(cognate)