utvrditi

1. (of facts) to establish; to determine
   Policija je utvrdila uzrok požara. — The police established the cause of the fire.
   Lekar je utvrdio da je sve u redu. — The doctor determined that everything was fine.
2. to set; to fix
   Utvrdili smo datum sastanka. — We set the date of the meeting.
   Vlada je utvrdila nove cene struje. — The government set new electricity prices.
3. to strengthen; to consolidate
   Ova pobeda je utvrdila njegovu poziciju lidera. — This victory strengthened his position as leader.
   Pre ispita treba da utvrdiš gradivo. — Before the exam you need to consolidate the material.
4. (military) to fortify
   Vojska je utvrdila grad pred napad. — The army fortified the city before the attack.
5. (reflexive: utvrditi se) to dig in; to entrench oneself
   Neprijatelj se utvrdio na brdu. — The enemy dug in on the hill.

In the sense "establish a fact" it is often followed by a clause: utvrditi da… The meaning "dig in, entrench oneself" is expressed by the reflexive form utvrditi se.