(NES pronounced like a word not an acromym)
A side effect of playing too much videogames. often accompanied with minor to moderate,but constant, pain. can last days even if gameing is discontinued also, pain not always restricted to one thumb. can be applied to a gamer regardless of the platform he\she is playing, but obvously derrived from the 8-bit NES days.
gorgeous girl:hey pete! wanna go to the mall?
pete:naw...i got a pretty bad case of nes thumb
gorgeous girl:geek! *stomps off never to speak the pete agian*
"curse you koopa troopa! now i have NES thumb"