Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Irish
teann
←
Proto-Celtic
*tanawyos
(derived)
←
Welsh
tynnu
(cognate)
←
Irish
teinn
(link)
←
Irish
i dteann
(link)
←
Irish
le teann
(link)
←
Proto-Indo-European
*ten-
(derived)
←
Middle Irish
tenn
(inherited)
←
Middle Irish
tendaid
(inherited)
←
Old Irish
tend
(inherited)