<p><strong>Noun</strong></p><ul><li>plural: thecae</li><li>a case or receptacle.</li><li><strong>Botany, Mycology:</strong> a sac, cell, or capsule; a sporangium.</li><li><strong>Anatomy, Zoology:</strong> a case or sheath enclosing an organ, structure, etc., as the horny covering of an insect pupa or the loose membrane covering the spinal cord.</li></ul>