The Collaborative International Dictionary
Plexus \Plex"us\, n.; pl. L. Plexus, E. Plexuses. [L., a twining, braid, fr. plectere, plexum, to twine, braid.]
(Anat.) A network of vessels, nerves, or fibers.
(Math.) The system of equations required for the complete expression of the relations which exist between a set of quantities.
--Brande & C.-
A network; an intricate or interwoven combination of elements or parts in a coherent structure.
In the perception of a tree the reference to an object is circumscribed and directed by a plexus of visual and other presentations.
--G. F. Stout.
Wiktionary
n. (plural of plexus English)
Usage examples of "plexuses".
In the membranes surrounding the ventricles there are intricate networks of fine blood vessels called chorioid plexuses (koh'ree-oid plek'sus-ez.
There is a resultant active circulation of the fluid from the chorioid plexuses, where it leaks out of the blood, through the ventricles, out into the sub-arachnoid space, and through the arachnoid villi, where it is absorbed back into the blood.