Is the word port a noun?

Yes, "port" can be a noun. It has several different meanings:

* A harbor or harbor town: "The ship docked at the port of Marseille."

* A place where a ship can load and unload cargo: "The port was bustling with activity."

* A bottle or opening in a container: "Pour the wine through the port."

* A type of fortified wine: "He prefers to drink port after dinner."

* A connector on a device: "Connect the USB port to your computer."

The specific meaning of "port" will depend on the context in which it is used.