What's NOS ???

[Zilverado]

OKay, I may be opening myself up to some shots here, but here goes.... (please be kind ).

What does NOS stand for when referring to parts - such as the headlight bezels that just sold on e-bay (mentioned in a recent post)?

I've heard of Nitrous Oxide Systems, but I doubt this is what NOS refers to in this context.

Please help - - or should I say - - "let the razzing begin"...