theca

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

1. a case or receptacle.
2. Botany, Mycology.
   1. a sac, cell, or capsule.
   2. a sporangium.
3. 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.

noun plural -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

n. pl. the•cae (-sē′, -kē′)

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

Plural thecae (thē′sē′, -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.