Note: The following is made available under GPL from http://codex.wordpress.org/GPL. It may be edited a little from its original form, but probably not a lot. There is no guarantee this information is accurate…use at your own risk.
Within the WordPress interface, “ping” is sometimes used to refer to Pingbacks and Trackbacks.
In general computer terms, “ping” is a common utility used in a TCP/IP environment to determine if a given IP Address exists or is reachable. Typically, Ping is used to diagnose a network connection problem. Many times you will be asked, “Can you ping that address?”. That means, does the Ping utility return a success message trying to reach the “problem” IP Address?