Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
sellout
←
Proto-Celtic
*sil-n-
(inherited)
←
Welsh
syllu
(cognate)
←
Irish
súil
(cognate)
←
Ancient Greek
στίλβω
(cognate)
←
Old Irish
solus
(cognate)
←
Middle Breton
sellet
(inherited)