What does MAC address refer to in networking?

The term MAC address specifically refers to a unique identifier assigned to network interfaces for communications on the physical network segment. This identifier, typically presented in a six-byte hexadecimal format, helps ensure that data packets are directed to the correct hardware device in a local area network. Each device's MAC address is distinct, allowing for precise network management and communications.

While a MAC address is indeed a unique numerical label, this definition is broader and does not specifically emphasize its role as an identifier for network interfaces, which is critical in distinguishing it from other types of identifiers. The other options do not accurately capture the essence of what a MAC address is and its function within networking. For example, connecting networks or data transfer protocols pertain to network functionality but do not define a MAC address itself.