Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
bras
←
Proto-Celtic
*brassos
(inherited)
←
Proto-Celtic
*brassos
(inherited(br/cy))
←
Welsh
bras
(cognate)
←
Cornish
bras
(cognate)
←
Cornish
broas
(mention)
→
Welsh
bras
(cognate)