Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
dourgi
←
Breton
dour
(compound)
←
Breton
ki
(compound)
←
Proto-Brythonic
*düβrgi
(inherited)
←
Proto-Celtic
*dubrokū
(inherited)