I applied to this site with the main aim to set you guys straight on this topic.
A 2-stage trigger is JUST that...A trigger with TWO available trigger-release weights.
When you take-up the initial slop before the trigger lets the hammer go, IT IS CREEP. Some (single stage adjustable) triggers allow you to remove all or most of the creep and adjust the pull weight. THIS IS STLL a single stage trigger.
A TWO stage trigger allows you to do the same thing, but gives you 2 choices of trigger pull weight. This type of trigger allows you to (A) just pull on the trigger in the "normal" range of an adjusted weight of 4 to 7 pounds. (B) if you want a super-low trigger release weight, you USUALLY push the trigger FORWARD, which puts the sear in the SECOND stage, with a (usually) available weight of around 1/2 ounce to 2 pounds...This is whats known as a HAIR TRIGGER...no varmint or sniper rifle should be without a TRUE 2-stage trigger.