Viewing Point — The place where you are, your eye level.
Viewing Angle — The place where you are, your eye level and the angle from your point of view.
Viewing Height — The place where you are, at your eye level and height or elevation.
Horizon Line — That place where the land and the sky meet.
Picture Plane — A make believe paper or canvas between you and what you are illustrating.
Vanishing Point — The single point on the horizon where all the lines on the ground level seem to be coming together.
Single Point Perspective — A single vanishing point on the horizon line.
Double Point Perspective — Two separate vanishing points on the horizon line.
Triple Point Perspective — Two vanishing points on the horizon and one in the sky or on the ground.
Light Reference — The point where your light source comes from for example the sun or a lamp.
Shadow Vanishing Point — A point directly under your light reference and on the horizon line or on the ground.
Foreshortening — To shorten the lines of (an object) in a drawing or other representation so as to produce an illusion of projection or extension in space.