Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
koumoul
←
Proto-Brythonic
*kuml
(inherited)
←
Welsh
cwmwl
(cognate)
←
Latin
cumulus
(borrowed)
→
Welsh
cwmwl
(cognate)