Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*extro-
→
Irish
eachdraidh
(derived(ga/gd))
→
Irish
eachtra
(derived)
→
Irish
eachtradh
(derived(ga/gd))