Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
bogh
←
Breton
boc'h
(cognate)
←
Proto-Brythonic
*box
(inherited)
←
Welsh
bogh
(cognate)
←
Scottish Gaelic
bòc
(cognate)
←
Latin
bucca
(borrowed)
→
Welsh
boch
(cognate)
→
Cornish
diwvogh
(prefix)