Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Indo-European
*Hróth₂os
→
Breton
rod
(inherited)
→
Cornish
ros
(inherited)
→
Old Irish
roth
(inherited)