Ping is a network utility used to test the reachability of a device on an Internet Protocol (IP) network. By sending a small packet of data, known as an "echo request," to a target device and waiting for a response, ping measures how long it takes for the data to travel to the destination and back. The results help diagnose network connectivity issues and assess the speed and reliability of a connection. Ping is commonly used by IT professionals to troubleshoot network problems and ensure devices are communicating properly.