Final answer:
A single unique network node is assigned an IP address, which can be an IPv4 or IPv6 address depending on the network, and serves as a unique identifier for communication within a computer network.
Step-by-step explanation:
The type of address that applies to a single unique network node is known as an IP address. An IP (Internet Protocol) address is a unique identifier assigned to each device connected to a computer network that uses the Internet Protocol for communication. This address allows devices to send and receive data across networks with clearly defined network paths. In most cases, when referring to a local network, this would be an IPv4 address like 192.168.1.1, or an IPv6 address in larger, newer networks, which could look something like 2001:0db8:85a3:0000:0000:8a2e:0370:7334. It is important for network administrators and technicians to understand how IP addresses operate within the network to diagnose connectivity issues and ensure a seamless flow of data.