Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Primitive Irish
ᚉᚐᚈᚈᚒ
←
Proto-Celtic
*katus
(inherited)
←
Welsh
cad
(cognate)
→
Irish
cath
(inherited)
→
Scottish Gaelic
cath
(inherited)
→
Manx
cah
(inherited)
→
Old Irish
cath
(inherited)