Entry 1 sense Webster, 1913 Corrugator /(k?r"r?-g?`t?r)/ · Cor·ru·ga·tor · IPA /ˈkɔɹ.əˌɡeɪ.tɚ/ 01 n. A muscle which contracts the skin of the forehead into wrinkles. 1. A muscle which contracts the skin of the forehead into wrinkles.(Anat.)