Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
dafad
←
Proto-Brythonic
*daβ̃ad
(inherited)
←
Proto-Celtic
*dametos
(inherited)
→
English
theave
(cognate)