Anatomy Either of two fleshy structures that surround the opening of the mouth in humans and other mammals. In humans, the smooth brownish to reddish border of the lip. A structure or part that encircles or bounds an orifice, as: Anatomy A labium. The margin of flesh around a wound. Either of the margins of the aperture of a gastropod shell. A rim, as of a vessel, bell, or crater. Botany One of the two divisions of a bilabiate corolla or calyx, as in the snapdragon, or the modified median petal of an orchid flower. The tip of a pouring spout, as on a pitcher. Slang Insolent talk. To touch the lips to. To kiss. To utter. To lap or splash against. Sports To hit a golf ball so that it touches the edge of (the hole) without dropping in.