What is a "packet" in networking?

A "packet" in networking refers to a unit of data that is transmitted over a packet-switched network. This concept is fundamental to how data communication works on the internet and many other networks. When data is sent from one point to another, it is broken down into smaller, manageable pieces called packets. Each packet contains not only the data being transmitted but also metadata, such as the destination address and the sequence number, which help in reassembling the data correctly at the receiving end.

The packet-switching method lowers the risk of congestion and allows for more efficient use of the network compared to older methods like circuit switching. By allowing different packets to take various routes through the network based on current conditions, packet-switching can maintain better overall performance and resilience.

The other options do not accurately define what a packet is in the context of networking. For instance, software applications and error-checking mechanisms are separate components within data communication. A type of computer virus is unrelated to the concept of packets, as it does not involve the transmission of data units in a network.