Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*koimos
→
Breton
kuñv
(inherited)
→
Welsh
cu
(inherited)
→
Irish
caomh
(inherited)
→
Scottish Gaelic
caomh
(inherited)
→
Old Irish
Cóemgen
(derived)
→
Old Irish
cóem
(inherited)