Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Irish
troigh
←
Proto-Celtic
*tregess
(inherited)
←
Proto-Indo-European
*tregʰ-
(derived)
←
Old Irish
traig
(inherited)