Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Manx
oe
←
Proto-Celtic
*awyos
(inherited)
←
Proto-Indo-European
*h₂ewh₂yos
(inherited)
←
Primitive Irish
ᚐᚃᚔ
(inherited)
←
Old Irish
úa
(inherited)
→
Manx
aa-oe
(prefix)