Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
-ar
←
Proto-Brythonic
*-ar
(inherited)
←
Proto-Celtic
*-aros
(inherited)
←
Welsh
byddar
(mention)
←
Proto-Indo-European
*-Hrós
(inherited)
→
Welsh
cynnar
(suffix)
→
Welsh
-gar
(compound)
→
Welsh
diweddar
(suffix)