Definition of theca in English:
noun (plural thecae /ˈTHēsē/)
1.2 Zoology A cuplike or tubular structure containing a coral polyp.
- It is notable that both specimens also display asymmetry in the overall structure of their thecae.
- In the ‘echinoderm’ reconstruction, the theca lies with the convex side upwards and the appendage is interpreted as an anterior feeding arm.
- The theca around the column is smooth, sometimes with weak longitudinal muscles.
1.3 Botany Either of the lobes of an anther, each containing two pollen sacs.
- As pollinators removed pollen from the thecae, their walls collapsed and the anthers curled down gradually.
- The percentage of thecae that dehisced longitudinally varied greatly among rice varieties.
- Stamens are didynamous, but the yellow anthers occur close together, with their divergent thecae spreading to the outside.
1.4 (also theca folliculi /fəˈlikyəˌlī/) Anatomy The outer layer of cells of a Graafian follicle.
- The term ‘follicle complex’ has been proposed to include the follicle, basement membrane, and the theca, including its blood vessels.
- The follicle is surrounded by a theca, derived from the stromal compartment of the ovary and is always separated from this compartment, throughout development and final oocyte maturation, by a basement membrane.
- Example sentences
- Magnetic resonance imaging of the pelvis showed a large sacral mass that replaced the sacrum and compressed the thecal sac, extending anteriorly into the pelvic cavity, occupying a major portion of it.
- Seawater is pumped through these canals and gas exchange takes place within the thecal interior.
- It clearly has plates that can reasonably be interpreted as thecal.
- Example sentences
- It is a widespread Paleozoic marine taxon that has been interpreted most recently as a tubiculous annelid or other ‘worm’ or as a thecate hydrozoan or scyphozoan cnidarian.
- The results suggest that intensive regenerative nutrient cycling or external nutrient inputs are a necessary precondition for an efficient trophic transfer of the energy stored in blooms of thecate dinoflagellates.
- This is a small thecate dinoflagellate, almost pear-shaped, with a conical anterior end and a round posterior.
Definition of theca in:
- British & World English dictionary
What do you find interesting about this word or phrase?
Comments that don't adhere to our Community Guidelines may be moderated or removed.
Most popular in the US
Most popular in the UK
Most popular in Canada
Most popular in Australia
Most popular in Malaysia
Most popular in Pakistan