Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
hav
←
Proto-Brythonic
*haβ̃
(inherited)
←
Proto-Celtic
*samos
(inherited)
←
Welsh
haf
(cognate)
←
Proto-Indo-European
*sm̥-h₂-ó-
(inherited)
←
Old Cornish
haf
(inherited)