Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Irish
Boidmal
←
Proto-Celtic
*boudi
(derived)
←
Proto-Celtic
*maglos
(derived)
←
Old Irish
buaid
(mention)
←
Old Irish
mál
(mention)