an exercise in which
a person, keeping a prone position with the hands palms down under the shoulders, the balls of the feet on the ground, and the back straight, pushes the body up and lets it down by an alternate straightening and bending of the arms.
(of a brassiere) having padding and usually underwires in the lower part of the cups so as to raise the breasts and make them seem fuller.
(of a sleeve) made to be pushed up the arm, away from the wrist or elbow, so as to create a puffed or creased fullness.
1905–10; noun use of verb phrase push up