Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Middle Irish
ógán
←
Old Irish
ócán
(inherited)
←
Old Irish
óc
(mention)
→
Irish
ógánach
(inherited)
→
Scottish Gaelic
òganach
(derived)
→
Scottish Gaelic
ògan
(inherited)
→
Manx
aegan
(inherited)