Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Irish
roithid
←
Proto-Celtic
*rotīti
(inherited)
←
Proto-Indo-European
*Hret-
(root)
←
Old Irish
reithid
(mention)