thecal
Word family
- thecanounC2
- intrathecaladjectiveC2
Synonym discussion
Sense: adjective/1
Thecal is used for something that belongs to or forms a specific protective sheath in anatomy. Capsular is close when a structure has a capsule, but it is broader and often used for joints, organs, or bacteria. Membranous is broader still and only says something is like a membrane, without pointing to a named sheath. Follicular relates to a follicle as a whole, while thecal focuses on the outer covering layer around it. Compare a thecal sac around the spinal cord, a capsular tear in a joint, and a membranous wall inside an organ.
Etymology
Thecal comes from the noun theca, a scientific word for a case or sheath that covers something. Theca entered modern scientific English through New Latin from Greek, where it meant a case or container. English then added the ending -al to make an adjective meaning 'relating to a theca' or 'forming such a covering.'
First known use
1666
1666, in the meaning defined above