-theca-

‖n.; pl. Thecae [ L., fr. Gr. &unr_; a case to put anything in. See Tick a cover. ] 1. A sheath; a case; as, the theca, or cell, of an anther; the theca, or spore case, of a fungus; the theca of the spinal cord. [ 1913 Webster ]

2. (Zool.) (a) The chitinous cup which protects the hydranths of certain hydroids. (b) The more or less cuplike calicle of a coral. (c) The wall forming a calicle of a coral. [ 1913 Webster ]