muscle definition for kids
Definition of MUSCLE for Kids. 1. : a tissue of the body consisting of long cells that can contract and produce motion. 2. : an organ of the body that is a mass of muscle tissue attached at either end (as to bones) so that it can make a body part move.. a: a body tissue consisting of long cells that contract when stimulated and produce motion b: an organ that is essentially a mass of muscle tissue attached at either end to a fixed point and that by contracting moves or checks the movement of a body part. 2.