<p><strong>Noun</strong></p><ul><li>The hair growing on the upper lip, such hair on men allowed to grow without shaving, and often trimmed in any of various shapes.</li><li>Hairs or bristles growing near the mouth of an animal.</li><li>A stripe of color, or elongated feathers, suggestive of a mustache on the side of the head of a bird.</li><li>Something resembling a mustache, as food or drink adhering to the upper lip: a mustache of milk.</li></ul>