What is the difference between a port and a protocol?

Protocol = how to communicate, Port = where to communicate
You can think of a port as a phone extension, with the computer's IP address being like its phone number. You can call the number (IP address) to talk to the computer, then dial the extension (port) to talk to a specific application. An application needs to be listening on a port in order to communicate.

A protocol is just the language that the two applications on either end of a conversation agree to speak in. If your application is sending streams of bytes to my application, my application needs to know how to interpret those bytes.