Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Polish
siedmio-
→
Polish
siedmiokąt
(affix)
→
Polish
Siedmiogród
(affix)
→
Polish
siedmioletni
(affix)
→
Polish
siedmiokrotny
(affix)
→
Polish
siedmiobój
(affix)