[ thee-kuh ]

noun,plural the·cae [thee-see]. /ˈθi si/.
  1. a case or receptacle.

  2. Botany, Mycology.

    • a sac, cell, or capsule.

    • a sporangium.

  1. Anatomy, Zoology. 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.

Origin of theca

1655–65; <Latin thēca, from Greek thḗkē “case, cover,” akin to tithénai “to place, put”

Other words from theca

  • thecal, adjective

Words Nearby theca Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use theca in a sentence

  • From its sides behind proceed the antenn-cases (Cera-theca); and before from the middle, the tongue-case (Glosso-theca).

  • A chronic inflammatory involvement of a theca through which an important tendon plays may cause adhesions to form.

    Lameness of the Horse | John Victor Lacroix
  • In addition to aspirating synovia, the introduction of equal parts of alcohol and tincture of iodin into the theca is necessary.

    Lameness of the Horse | John Victor Lacroix
  • The body is often provided with not-living external formations “stalk” and “theca” (or “lorica”).

  • The word theca signified in classical Latin a case or receptacle in which any object was kept.

    The Care of Books | John Willis Clark

British Dictionary definitions for theca


/ (ˈθiːkə) /

nounplural -cae (-siː)
  1. botany an enclosing organ, cell, or spore case, esp the capsule of a moss

  2. zoology a hard outer covering, such as the cup-shaped container of a coral polyp

Origin of theca

C17: from Latin thēca, from Greek thēkē case; related to Greek tithenai to place

Derived forms of theca

  • thecal or thecate, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for theca


[ thē ]

Plural thecae (thēsē′, -kē′)
  1. A case, covering, or sheath, such as the pollen sac of an anther, the spore case of a moss, or the outer covering of the pupa of certain insects.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.