Matter bridge
A Matter bridge is a hub that represents its non-Matter devices — typically Zigbee — as Matter devices, so ecosystems like Apple Home can control them. The Philips Hue Bridge, Aqara hubs, IKEA DIRIGERA, and Bosch Smart Home Controller II all do this: pair a bulb to the bridge, and it appears in your Matter ecosystem as if it were a native Matter light.
In the Matter spec a bridge is an Aggregator device type: one Matter node that exposes each bridged device as a separate endpoint with its own device type. The bridged devices keep speaking Zigbee (or another protocol) to the bridge; only the bridge speaks Matter. Add or remove a device on the bridge and the change propagates to every connected ecosystem automatically.
Bridging maps the basics — on/off, brightness, color, sensor readings — but features with no Matter equivalent stay in the maker’s app: Hue’s entertainment sync and scene engine, for example, do not cross the bridge. That trade-off, and when bridging beats pairing a device natively, is covered in our guide on how Matter bridges work.