opseg

1. extent; scope
   Opseg posla je veći nego što smo mislili. — The scope of the work is bigger than we thought.
   Još se ne zna pravi opseg štete. — The real extent of the damage is still unknown.
2. (of frequencies, voice, values) range
   Ona ima neverovatan opseg glasa. — She has an incredible vocal range.
   Ruter radi u opsegu od 5 GHz. — The router works in the 5 GHz band.

For the circumference of a circle or waist size, Serbian usually uses obim.