Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Middle Irish
casán
←
Middle Irish
cos
(affix)
←
Middle Irish
-án
(affix)
←
Middle Irish
cosán
(link)
→
Irish
cosán
(inherited)
→
Scottish Gaelic
casan
(inherited)
→
Manx
cassan
(inherited)