Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Gaulish
Cebenna
→
Breton
kein
(cognate)
→
Welsh
cefn
(cognate)
→
Middle Welsh
keuen
(cognate)