Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Polish
tydzień
←
Proto-Slavic
*tъdьnь
(inherited)
→
Polish
tygodnik
(affix)
→
Polish
tygodniówka
(affix)