Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Bulgarian
хребет
←
Bulgarian
хръбе́т
(doublet)
←
Russian
хребе́т
(borrowed)
←
Proto-Slavic
*xrьbьtъ
(derived)