Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
pegh
←
Breton
pec'hed
(cognate)
←
Proto-Brythonic
*pexọd
(inherited)
←
Middle Cornish
pegh
(inherited)
←
Welsh
pechod
(cognate)
←
Latin
peccātum
(derived)
→
Welsh
pechod
(cognate)