Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
ki
←
Proto-Brythonic
*ki
(inherited)
←
Proto-Celtic
*kū
(inherited)
←
Proto-Indo-European
*ḱwṓ
(inherited)
→
Cornish
dowrgi
(compound)
→
Cornish
morgi
(compound)