BRB
BRB is chat shorthand for 'be right back'.
The simple explanation
BRB is internet shorthand for 'be right back'. Players type it in the chat of an online table when they leave for a short moment, such as fetching a drink or answering the door. It is a courtesy that tells other players not to wait for you.
A closer look
Typing BRB does not pause the clock. At an online table the timer keeps running, and if you do not act in time your hand is folded or checked automatically. The right way to step away is to sit out before you leave, so that you are skipped. BRB is best understood as a polite message and not as a function of the software. Related shorthand includes AFK, which means away from keyboard.
A practical example
A player types 'brb 1 min' in chat and sits out.
Full explanation
BRB is chat shorthand for ‘be right back’.
BRB stands for ‘be right back’. It is chat shorthand used on the internet, including at online poker tables, for a short absence.
At a poker table, a player who needs to step away types it to let the others know. The message does not stop the game, so the hand may continue without him.
The safest approach is to use the sit out button before you leave. The software then skips your hands and posts blinds according to the site’s rules.
Other chat shorthand you may meet includes AFK, BTW and GL, short for good luck.
Alternative spelling: Be Right Back