Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Russian
собо́р
→
Belarusian
сабор
(cognate)
→
Russian
сбор
(doublet)
→
Russian
соборянин
(affix)
→
Russian
соборный
(affix)