The brb full form is Be Right Back. BRB is a phrase commonly used while chatting on social networking sites such as Gmail, Yahoo Messenger, Watsapp, Facebook, and others.
When you take a break from a topic in an online chat room for a brief period of time.
B = Be
R = Right
B = Back
It’s used to describe a circumstance in which a person is conversing online with someone and wishes to let them know that “I’ll be back to this topic momentarily.”
As a result, it is a typical internet slang expression used by a user to indicate that he expects to be away from his phone, laptop, or computer for a brief period of time.
It’s also a manner of showing civility to the other user, so he doesn’t have to wonder why someone hasn’t responded in a while. In online talking, this type of issue may arise regularly.
Acronyms are increasingly common in online talking these days, therefore users often use BRB instead of Be Right Back.