Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old East Slavic
бꙑти
→
Belarusian
быць
(inherited)
→
Russian
быть
(inherited)
→
Russian
былина
(mention)
→
Ukrainian
бути
(derived)