Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*meldo-
→
Breton
melc'hwed
(derived)
→
Welsh
malwod
(derived)
→
Cornish
melhwes
(derived)