Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Irish
ramhar
←
Proto-Celtic
*remros
(inherited)
←
Old Irish
remor
(inherited)
→
Irish
ceannramhar
(prefix)
→
Manx
roauyr
(cognate)