Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
bleujenn
←
Proto-Celtic
*blātus
(derived)
←
Welsh
blodyn
(cognate)
←
Proto-Indo-European
*bʰleh₃-
(derived)
←
Cornish
(suffix)
←
Cornish
en
(suffix)