Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old English
brocc
←
Proto-Celtic
*brokkos
(derived)
←
Welsh
broch
(cognate)
←
Irish
broc
(cognate)
←
Cornish
brogh
(cognate)