Lateral Plane

Movements performed in front of and parallel to the body.

Leap

A jump from one foot, onto the other foot (See Jete)

Legmount

A balance with the free leg strait and lifted to a front or side split position with a strait support leg. The free leg can be held with hands, apparatus, or completely free to add extra difficulty.

Leotard

A close-fitting garment made from stretchy material (such as lycra) to allow the gymnast a great range of movement.

Line

The shape made by positioning your body and limbs (ie: to have good body line is to have good positioning)

Lunge

position with one foot well in front of the other, with the front knee bent and most of your wieght on it (often used as preparation for a pivot)
(Picture from Nikki Johnson)