As initialisms the difference between brb and gtg
is that brb is (I'll) be right back while gtg is got to go (as a form of farewell.
brb
Translingual
Symbol
(
head)
The ISO 3166-1 three-letter (alpha-3) code for Barbados
ISO 3166-1
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gtg
English
Initialism
(Initialism)
(head)
(Internet) got to go (as a form of farewell )
(Internet) get-together
(Internet) good to go
See also
* brb