Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Irish
ardathair
←
Irish
ard-
(affix)
←
Irish
athair
(affix)
←
Scottish Gaelic
àrd-athair
(cognate)
←
Manx
ard-ayr
(cognate)
→
Scottish Gaelic
àrd-athair
(cognate)
→
Manx
ard-ayr
(cognate)