desetina

1. (plural + gen.) tens; dozens
   Na protest su izašle desetine hiljada ljudi. — Tens of thousands of people turned out for the protest.
   Dobio sam desetine poruka za rođendan. — I got dozens of messages on my birthday.
2. one tenth
   Pobedio je za desetinu sekunde. — He won by a tenth of a second.
   Samo desetina studenata je položila ispit. — Only a tenth of the students passed the exam.
3. (military) squad; section
   Komandir desetine je izdao naređenje. — The squad leader gave the order.
4. (singular + gen.) a group of ten; about ten
   Na sastanak je došla desetina ljudi. — About ten people came to the meeting.

The approximate quantity "about ten" is usually expressed with desetak (desetak ljudi); singular desetina more often means "one tenth", so desetina ljudi can be ambiguous.