Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
ffwrn
←
Proto-Brythonic
*furn
(inherited)
←
Cornish
forn
(cognate)
←
Latin
furnus
(derived)
←
Middle Welsh
ffwrn
(inherited)
→
Cornish
forn
(cognate)