Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
gwn
←
Proto-Celtic
*wind-nu
(inherited)
←
Cornish
gonn
(cognate)
←
Old Irish
ro·finnadar
(cognate)
←
Middle Breton
goun
(cognate)
←
Middle Breton
gonn
(mention)
→
Old Irish
rofinnadar
(cognate)