Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Irish
lasair
←
Proto-Celtic
*laxsarā
(inherited)
←
Old Irish
lasar
(inherited)
→
Irish
Lasairfhíona
(compound)
→
Irish
lasairdhíonach
(compound)