Plie ('bend') is the most important basic technique that one must master perfectly to be a technically strong dancer.
Demi Plie
A half-bending action of the knees over the toes, with the heels remaining firmly on the floor. The back held erect throughout.

Grand Plie
A full bending of the knees over the toes. It is used to develop the strength and control of the whole body.Maximum turnout should be maintained, with the back held erect throughout the movement.