Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Indo-European
*dʰus-no-
→
Irish
donn
(derived)
→
Irish
Donn
(derived)
→
Old Irish
donn
(derived)