hartija

1. paper
   Baka je sve zapisivala na listu hartije. — Grandma wrote everything down on a sheet of paper.
2. (in hartije od vrednosti) securities
   Banka je uložila novac u hartije od vrednosti. — The bank invested the money in securities.

In everyday speech papir is more frequent; hartija is also standard but somewhat more formal or bookish, and it is the obligatory word in the term hartije od vrednosti.