back channel

plural back channels

1. The smaller of two channels in a river that diverge to form an island.
2. A secondary channel of activity, typically in parallel with primary channels and somewhat independent of them.
3. An unofficial communications channel used to make informal or subversive negotiations.
4. computingA real-time online discussion that occurs simultaneously with a verbal presentation.

   TodaysMeet visualizes collaborative and parallel conversations in a backchannel through a digital classroom where every student has a voice.

   2017, Di Zou, James Lambert, “Feedback methods for student voice in the digital age”, in British Journal of Educational Technology, volume 48, number 5, page 1083

5. human sciencesA gesture or short prompt by which a listener invites a speaker to continue.