Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Manx
keirdaght
←
Proto-Celtic
*kerdā
(derived)
←
Manx
keird
(affix)
←
Manx
-aght
(affix)
←
Proto-Indo-European
*kerd-
(derived)
←
Old Irish
cerd
(derived)