Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Irish
og
←
Proto-Celtic
(mention)
→
Irish
ubh
(inherited)
→
Scottish Gaelic
ugh
(inherited)
→
Manx
ooh
(inherited)