Bros is an informal, casual way to refer to male friends or buddies, shortened from “brothers.” When someone says “hanging out with my bros,” they mean spending time with their close guy friends. The word suggests a relaxed, friendly bond, like teammates who grab pizza after practice or classmates who always sit together at lunch.

While bros aren't actually related by blood, the word borrows the idea of brotherhood to describe friendship. Two boys who meet on the first day of school and quickly become best friends might call each other bros. The word captures that easy, loyal friendship where you've got each other's backs.

You'll also hear bro used directly, like “Hey, bro!” as a friendly greeting, similar to “dude” or “friend.” Sometimes people use it more broadly to describe a certain style or personality: someone who's really into sports, video games, and hanging out with friends might be called a bro.

The word is quite casual. You probably wouldn't use it in a school report or when meeting a teacher or principal. But among friends your own age, calling someone your bro is a simple way to show you value their friendship.