I think this may help some who are a bit confused on what ping actually is:
ping 2 (pĭng) Pronunciation Key
n. A protocol that sends a message to another computer and waits for acknowledgment, often used to check if another computer on a network is reachable.
Ping(Packet Internet Groper) is a computer network tool used to test whether a particular host is reachable across an IP network; it is also used to self test the network interface card of the computer, or as a speed test. It works by sending ICMP “echo request” packets to the target host and listening for ICMP “echo response” replies. Ping estimates the round-trip time, generally in milliseconds, records any packet loss, and prints a statistical summary when finished.
The word ping is also frequently used as a verb or noun, where it can refer directly to the round-trip time, the act of running a ping program or measuring the round-trip time.
Also from Wiki's article:
In gaming
Main article: ping (video games)
In network multiplayer games like Unreal Tournament, Quake, Battlefield 2142, Call of Duty 4, Battlefield 2, Battlefield 1942, etc., the server notes the time it requires for a game packet to reach a client and a response to be received. This round-trip time is usually reported as the player's 'ping'. It is used as an effective measurement of the player's lag, with lower ping times being desirable. Note that this style of ping typically does not use ICMP packets.
Links Used: Dictionary.com definition:
http://dictionary.reference.com/browse/ping
Wikipedia:
http://en.wikipedia.org/wiki/Ping scroll down and you will see the In Gaming one....
Hope it helps clear some things up. If not oh well, I had a huge fail and it can be locked.