back-channel
adjective[before noun]
ukususing a different orunofficialmethodofcommunication:
There have beenreportsaboutinformalback-channelpeacetalksbetween the twogovernments.
back-channelnegotiations/communication
back channel
noun[C]
You caninvolvetheaudiencein apresentationbyincorporatinga backchannelwith which they cansuggestquestions, andcommenton each other'squestions.