Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Old Polish
płoski
←
Proto-Slavic
*ploskъ
(inherited)
→
Belarusian
плоскі
(cognate)
→
Polish
płaski
(inherited)