<p><strong>Adjective:</strong></p><ul><li>Reentrant:<ul><li>Reentering or pointing inward: a reentrant angle.</li></ul></li></ul><p><strong>Noun:</strong></p><ul><li>Reentrant:<ul><li>A reentering angle or part.</li><li>A person or thing that reenters or returns: Reentrants to the engineering program must take the introductory course again.</li><li>In physical geography: A prominent indentation in a coastline.</li></ul></li></ul>