Ping

Minimap
Ping usually means to click on the Minimap, highlighting a location for others in the party. This can be useful for pointing out flag runners in WSG, pointing out hard-to-see objects like Serpentbloom in Wailing Caverns, or just plain flipping out and irritating the party.

Latency
Some players of a technical bent might use "ping" to refer to how much lag they have, after the classic networking tool.