trk

1. run; running
   Stigao je na stanicu trkom, sav zadihan. — He got to the station at a run, all out of breath.
   Konj je iz koraka prešao u trk. — The horse went from a walk into a run.

2. colloq. (as a command) run!; quick!
   Trk u prodavnicu po hleb! — Quick, run to the shop for some bread!

Often used in the instrumental form trkom, 'at a run'.