i don't know, they're definitely not Polish words, but there is the surname Korecz (Hungarian though) and Korc i tried as well.
Here is a list of places with Korcz:
Korczew
Korczmin
Korczowa
Korczowiska
Korczyn
Korczyna
Korczyska
Korczów
Korczówka
Korczówka Kolonia