1. Criminal law. The entry of the penis or some other part of the body or a foreign object into the vagina or other bodily orifice. • This is the typical meaning today in statutes defining sexual offenses. — Also termed intromission. See RAPE(1).
2. The depth reached by a bullet or other projectile in something against which the projectile is fired.
3. The act of piercing or passing something into or through a body or object. — penetrate, vb.
