Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
duw
←
Proto-Celtic
*dēwos
(inherited)
←
Irish
dia
(cognate)
←
Proto-Indo-European
*dyew-
(root)
←
Proto-Indo-European
*deywós
(inherited)
→
Cornish
Duw
(mention)
→
Cornish
duwes
(suffix)