Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
hen
←
Proto-Brythonic
*hen
(inherited)
←
Proto-Celtic
*senos
(inherited)
←
Proto-Indo-European
*sénos
(inherited)
→
Breton
hendad
(prefix)
→
Breton
henvrezhoneg
(mention)