Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
godhvos
←
Breton
gouzout
(cognate)
←
Proto-Celtic
*wid-
(derived)
←
Welsh
gwybod
(cognate)
←
Proto-Indo-European
*weyd-
(derived)
←
Cornish
bos
(mention)
←
Old Cornish
*godbod
(inherited)
→
Breton
gouzout
(cognate)