In a Cisco TelePresence conference that is hosted on a Cisco MCU, a single pane shows the person who is currently talking. What is this pane called?

Host refers to the chairperson or organizer role in a conference, not a display pane that dynamically switches to show the current talker.

Active participant is not standard Cisco MCU terminology for the voice-activated speaker pane; it has no defined meaning in the MCU layout model.

Cisco MCU uses the term 'active speaker' to describe the voice-activated pane that tracks and displays the participant currently producing audio above the silence threshold. This feature implements automatic speaker detection, allowing remote participants to see the current talker in a dedicated pane without manual layout changes. It is a core Cisco MCU layout concept documented in the MCU administration and user guides.

Active floor is not the Cisco MCU term for the current-talker pane; floor control is a separate conferencing concept related to speaking rights, not a display pane label.