Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
ewyn
←
Breton
ewon
(cognate)
←
Proto-Brythonic
*owin
(inherited)
←
Cornish
ewyn
(cognate)
→
Irish
uan
(cognate)
→
Cornish
ewyn
(link)