A protocol is basically a foundational layer of code that tells something how to function. It’s the program that forms the software basis of any given network. Think of a protocol as a set of rules that allow entities to communicate and transmit information.
Protocols are not specific only to cryptocurrency. They exist in many places. On the Internet, protocols enable websites to function. The most common internet protocols are HTTP and HTTPS – though you might also see TCP/IP and SMTP.