pozadina

1. background
   Na slici se u pozadini vidi Kalemegdan. — Kalemegdan can be seen in the background of the photo.
   Promenio sam pozadinu na telefonu. — I changed the wallpaper on my phone.
2. (of events) background; underlying reasons
   Niko ne zna pravu pozadinu te afere. — No one knows the real background of that scandal.
3. (military) rear; home front
   Ranjenike su prebacili u pozadinu. — The wounded were moved to the rear.
4. colloq. humor. behind; backside
   Pao je na led i udario pozadinu. — He fell on the ice and hurt his backside.
5. (of a place) back; rear; area behind something
   Magacin se nalazi u pozadini prodavnice. — The storeroom is at the back of the shop.

The phrase "u pozadini" means "in the background", including for apps running in the background.