1620, "to drive along, thrust forward," from L. protrudere "thrust forward," from pro- "forward" + trudere "to thrust" (see extrusion). Intransitive meaning "stick out" first recorded 1626.
Main Entry: pro·trude Pronunciation: prO-'trüd Function: verb Inflected Forms: pro·trud·ed; pro·trud·ing transitive senses : to cause to project protrudes the lower lip —Gray's Anatomy> protrudeintransitivesenses : to jut out from the surrounding surface