Definition of: muscle

(mus′əl) noun
1. Anat. An organ composed of tissue arranged in bundles of fibers, by whose contraction bodily movements are effected. Two principal types are known: striated (striped), involved in voluntary movements, and smooth (unstriped), acting independently of the will. The heart muscle belongs anatomically between the two.
2. The tissue of the muscular organs.
3. Muscular strength.
—v.i. ·cled, ·cling To push in or ahead by sheer physical strength. ♦ Homophone: mussel. [<F <L musculus, lit., little mouse, dim. of mus. Doublet of MUSSEL.]