Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Latin
Celta
←
Latin
Celtae
(back-formation)
→
English
Celt
(mention)
→
Spanish
celta
(inherited)
→
Dutch
Kelt
(mention)
→
Portuguese
céltico
(mention)