Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
rod
←
Proto-Brythonic
*rrod
(inherited)
←
Proto-Celtic
*rotos
(inherited)
←
Proto-Indo-European
*Hróth₂os
(inherited)
→
Breton
divrod
(prefix)