No, they are 2 completely different things.
Thread is a mesh network protocol specifically designed for smarthome devices to use instead of WiFi or Bluetooth which both have limitations since they are primarily built for other use cases.
Matter is a communication standard, a common language for smarthome devices to speak to other with instead of Apple, Google, Amazon, Samsung, etc. all having different ones that devices need to support. Matter also requires that devices can be controlled locally, instead of relying on cloud servers for control.