Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
brogh
←
Proto-Brythonic
*brox
(inherited)
←
Proto-Celtic
*brokkos
(inherited)
→
English
brock
(cognate)
→
Old English
brocc
(cognate)