Plie means "to bend or fold" in French, and is executed by standing with the feet flat on the ground in one of the basic ballet positions and bending the knees. A plie combination may also include lifting the heels up to balance on the toes, or on "eleve." A plie creates the flexibility and alignment needed for jumps and turns.
Tendu means "to stretch" in French. A tendu consists of stretching or pointing the foot to the front, side and back of the body. The hip must not move with the leg and the foot must stay straight and in contact with the ground. The tendu trains the foot to point and strengthens it. This pointed foot aesthetic is the basis for classical ballet.
Ronde de jambe means "rounding of the leg" in French. With the ronde de jambe, you start with a tendu and make a semi circle on the ground with the foot instead of drawing it back to a close immediately. The hip should not go forward, back or to the side with the leg in a ronde de jambe. Ronde de jambes train the leg to work in isolation, which is important for kicks and extensions in advanced classical ballet.
Petit battement, small beats with the foot, are completed by bringing a pointed foot to the front and back of the ankle rapidly, keeping the standing leg still. Petit battements help in articulation with small jumps. Both men and women must develop the speed and control to execute the switches and rapid change of position in the air when executing fast jumps.
The final barre exercise is always grand battements (large kicks). These are done at the end of the barre session when the leg muscles are properly warmed and stretched. Grand battements bring the leg straight up as high as it can go. These prepare the dancer to execute high, straight leaps and high kicks and impressive extensions.