Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Cornish
drog
←
Proto-Brythonic
*drug
(inherited)
←
Proto-Celtic
*drukos
(inherited)
←
Welsh
drwg
(cognate)
←
Old Irish
droch
(cognate)