[a. mod.L. corrūgātor, agent-n. f. corrūgāre to CORRUGATE.]
1. Anything that corrugates or causes corrugation. rare.
1782. A. Monro, Anat., 215. Styptics, and other like corrugators, are vainly applied.
2. Anat. Each of the two small muscles that contract the brows in the action of frowning.
[1706. Phillips, Corrugator Supercilii.]
1839. Todd, Cycl. Anat., II. 280/2. The corrugator and frontalis muscles.
1872. Darwin, Emotions, ix. 222. The corrugators, by their contraction, lower the eyebrows and bring them together, producing vertical furrows on the forehead, that is, a frown.