A worm is a type of malware that replicates itself to spread rapidly through a computer network. Unlike a virus, a worm does not need a host program or human interaction to infect other devices. A worm can consume network bandwidth, slow down the system performance, or deliver a malicious payload, such as ransomware or a backdoor123. References: Types of Malware & Malware Examples - Kaspersky, 10 types of malware + how to prevent malware from the start, Computer worm - Wikipedia

A worm replicates through the network while a virus replicates, not necessarily to spread through the network.