Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
ffynnon
←
Breton
feunteun
(cognate)
←
Proto-Brythonic
*funtọn
(inherited)
←
Cornish
fenten
(cognate)
←
Latin
fons
(derived)
←
Old Welsh
finnaun
(inherited)
←
Old Welsh
fynnaun
(mention)
←
Middle Welsh
ffynnawn
(inherited)