Thread is a network layer
It carries IP traffic; Matter is the application protocol that can run over it.
Mains-powered Thread devices can route
Suitable always-powered Thread devices can help extend the mesh.
Battery devices behave differently
Low-power end devices typically communicate through parent devices rather than forwarding other devices' traffic.
A border router connects networks
A Thread Border Router links the Thread mesh to other IP networks such as Wi-Fi or Ethernet.
Keep in mind. Compatibility is not permanent. Confirm the current manufacturer, platform and certification information before purchasing, resetting or migrating a device.