Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Breton
ledan
←
Proto-Brythonic
*llɨdan
(inherited)
←
Proto-Celtic
*ɸlitanos
(inherited)
→
Irish
leathan
(cognate)
→
Manx
lhean
(cognate)
→
Old Irish
lethan
(cognate)