Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Russian
ту́ча
→
Bulgarian
туча
(cognate)
→
Polish
tęcza
(cognate)
→
Russian
тучевой
(affix)
→
Russian
тучка
(affix)