Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
gallos
←
Breton
gallout
(cognate)
←
Proto-Celtic
*galnati
(inherited)
←
Welsh
gallu
(cognate)
→
Breton
gallout
(cognate)