You can absolutely mute a microphone, since you can say "I muted my microphone" and any English speaker will understand exactly what you mean. edit: in fact I

You can absolutely mute a microphone, since you can say "I muted my microphone" and any English speaker will understand exactly what you mean. edit: in fact I would go so far as to say that the majority of English speakers, at least here in America, would prefer saying "mute the mic" instead "put the mic on mute" (I've never heard anyone say the latter in actual conversation, to be honest).