Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Middle Irish
cích
←
Proto-Celtic
*kīkos
(inherited)
←
Welsh
cig
(cognate)
→
Welsh
cig
(cognate)
→
Irish
cíoch
(inherited)
→
Scottish Gaelic
cìoch
(inherited)