TAKE-UP is any amount of trigger movement from the trigger’s initial resting position up until the point that the sear breaks and causes the gun to go “bang.” Take-up, the Wall, and Creep are all part of PreTravel, so when correctly using the term Pre-travel, you’d be referring to the combination of those three elements.
SLACK is any “positive” (pulling the trigger toward you) movement of the trigger that does not cause the sear to move and does not engage the mainspring.
THE WALL is the point where the trigger action first engages the resistance of the sear. In a single-stage trigger, the wall is immediately after the slack. In a two-stage trigger, the wall is after the first stage.
CREEP is any positive movement of the trigger that causes the sear to move but does not cause the trigger to break.
BREAK is the point of the trigger action where the sear releases the hammer.
OVER TRAVEL is any amount of “positive” trigger movement following the Break.
RESET is forward movement of the trigger to the point that the trigger re-engages the sear.
A roller bearing between the hammer and sear creates almost zero creep, a smooth pull and the shortest rest I've ever felt.