Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
gwynn
←
Proto-Brythonic
*gwɨnn
(inherited)
←
Proto-Celtic
*windos
(inherited)
→
Cornish
tas-gwynn
(affix)
→
Cornish
tasow-wynn
(affix)
→
Cornish
gwynnrudh
(compound)
→
Cornish
rudhwynn
(compound)