Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Irish
tomhais
←
Proto-Celtic
*to-
(derived)
←
Proto-Celtic
*messus
(mention)
←
Irish
(link)
←
Proto-Indo-European
*med-
(derived)
←
Old Irish
toimsid
(inherited)
←
Old Irish
tomus
(mention)