Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Proto-Celtic
*letos
→
Irish
le
(derived)
→
Irish
leath
(inherited)
→
Scottish Gaelic
leth
(inherited)
→
Old Irish
la
(derived)
→
Old Irish
leth
(inherited)