Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
danadl
←
Breton
linad
(cognate)
←
Irish
neantóg
(cognate)
←
Scottish Gaelic
deanntag
(cognate)
←
Cornish
linas
(cognate)
→
Welsh
danadl poethion
(compound)
→
Welsh
marddanadl
(compound)