A huddle room is a small meeting space for two to four people, designed for quick, informal sessions: a video call, a 1:1, a problem-solving session. They exist because most meetings are small, while most legacy meeting rooms were built for ten.
Huddle rooms only relieve pressure on big rooms if people can grab them fast. Bookable-at-the-door or app-based reservation, with the room visible on the floor plan, is what makes them work.