Sub-Model: An individual part of a model such as the handle on a switch or hand on an arm.  Note that a sub-model can be as little as one face.  In fact, that's what glows and gunpoints are; one-faced sub-models with specific properties assigned to them.

Pivot Point: The origin point of a submodel. It's from that point that it determines it's motion when a translation (move) or rotation key is assigned to it.  When you bend an arm at the elbow, the eldow is the forearm's pivot point.  The wrist would be the hand's pivot point.  You can set the pivot point to be anywhere in relation to it's sub-model.

Parents, Children, and Siblings:  This how we refer to the relations among sub-models that are attatched (logically, not physicaly) to each other.  An Arm is the easiest example:  A hand is a child of the forearm.  The forearm is the parent of the hand. Fingers are individual children of the hand and are sibling to the other fingers of the same hand (same parent).

Frame: An animation increment.

Key: A discription of a motion the a submodel performs within one frame.  There are 2 types of keys: Translation and Rotation. Translation is the movement from one X,Y,Z coordinate to another such as a  piston moving up.  It would take another Translation key to move the piston back down.  A Rotation key rotates a submodel around an axis a set amount of degrees.  Examples would be a door swinging on it's hinge, a powerup spinning, an arm bending at the elbow.

GunPoint:  A point from which a weapon is fired or object is spewed.  It is created by converting a single face submodel to a GunPoint.