Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
mad
←
Proto-Brythonic
*mad
(inherited)
←
Proto-Celtic
*matis
(inherited)
→
Scottish Gaelic
math
(cognate)
→
Manx
mie
(cognate)
→
Old Irish
maith
(cognate)