Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
reun
←
Breton
reunig
(cognate)
←
Irish
rón
(cognate)
←
Scottish Gaelic
ròn
(cognate)
←
Manx
raun
(cognate)
→
Scottish Gaelic
ròn
(cognate)
→
Manx
raun
(cognate)