- (telecommunications) round-trip time
- (computer graphics) render-to-texture
(Real-Time Text) Text that is transmitted as it is being typed. RTT is used in closed captioning as well as TDD/TTY systems for the hearing impaired. It may also be used in instant messaging (IM); however, the majority of IM systems transmit the entire message when the user hits Send. See TDD/TTY and closed captions.