Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
syfi
←
Breton
sivi
(cognate)
←
Proto-Celtic
*subi
(inherited)
←
Irish
sú
(cognate)
←
Proto-Indo-European
*sewH-
(derived)
←
Cornish
sevi
(cognate)
→
Welsh
syfïa
(affix)
→
Irish
sú
(cognate)