v: The act of staring over a DJ's shoulder to see what records he's spinning..
Originated from the British phenomenon of train geeks waiting on train platforms, notebooks in hand, recording the types and numbers of trains coming into the station.
Also the name of a famous book by Irvine Welsh in 1993, later made into a much more famous movie in 1996 by the same name. The word at the time referred to dance music geek culture, but was about the wasting of Scottish heroin addicts.
"I went to the club last night to hit on this bad-ass DJ chick, but the records she brought were amazing, so I just sat near her at the decks trainspotting them all night!"