prtljažnik

1. (of a car) trunk; boot
   Stavi kese u prtljažnik. — Put the bags in the trunk.
   Prtljažnik je pun, nema mesta za kofer. — The boot is full, there's no room for the suitcase.
2. (on a roof, bicycle) luggage rack; roof rack
   Kupili smo krovni prtljažnik za more. — We bought a roof rack for the trip to the seaside.

In everyday speech a car trunk is often called "gepek".