theca

noun

1. 1

   Any external case or sheath.

2. 2

   The pollen-producing organ usually found in pairs and forming an anther.

3. 3

   The twin layers of cells surrounding the basal lamina of an ovarian follicle.

4. 4

   The membrane complex enveloping the cells of certain plankton including diatoms and dinoflagellates.

5. 5

   The calcareous wall of a corallite, the exoskeleton of a coral polyp.

6. 6

   A case for the corporal cloth used in the Eucharist.