Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Irish
teichid
←
Proto-Celtic
*tekʷeti
(inherited)
←
Proto-Indo-European
*tekʷ-
(root)
←
Proto-Indo-European
*tekʷ-
(derived)
→
Old Irish
adteich
(affix)