noun, plural the·cae [thee-see] /ˈθi si/.

a case or receptacle.
Botany, Mycology.
  1. a sac, cell, or capsule.
  2. a sporangium.
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.

Nearby words

  1. thebaid,
  2. thebaine,
  3. theban,
  4. thebe,
  5. thebes,
  6. theca cordis,
  7. theca folliculi,
  8. theca-cell tumor,
  9. thecal,
  10. thecal sac

Origin of theca

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

Related formsthe·cal, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for theca

British Dictionary definitions for theca


noun plural -cae (-siː)

botany an enclosing organ, cell, or spore case, esp the capsule of a moss
zoology a hard outer covering, such as the cup-shaped container of a coral polyp
Derived Formsthecal or thecate, adjective

Word Origin for theca

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

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

Medicine definitions for theca



n. pl. the•cae (-sē′, -kē′)

A case, covering, or sheath, such as the outer covering of the cocoon of certain insects.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for theca



Plural thecae (thēsē′, -kē′)

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.