Final answer:
The term 'protocol' refers to the set of rules that determine how a network operates, functioning as a language for devices to communicate.
Step-by-step explanation:
The term that refers to the set of rules that define how a network operates is protocol. In the context of computer networks, a protocol is akin to a language that devices use to communicate with each other. It ensures that data is transferred accurately and securely across a network, and each protocol has specific rules and conventions that must be followed. Different protocols are used for different types of communication on a network, such as HTTP for web traffic or SMTP for email.