Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*dagos
→
Welsh
da
(inherited)
→
Irish
dea-
(mention)
→
Scottish Gaelic
deagh
(inherited)
→
Cornish
dâ
(inherited)
→
Old Irish
andach
(derived)