plexus

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A structure in the form of a network, especially of nerves, blood vessels, or lymphatics.
• noun A combination of interlaced parts; a network.

from The Century Dictionary.

• noun A network; any collection of intimately coherent parts, as of an argument.
• noun In anatomy, an interlacing of nerves, vessels, or fibers; a net-like arrangement of parts, or the parts so disposed: especially said of certain delicate vascular membranes chiefly composed of minute anastomosing blood-vessels, as the choroid plexus, and of similar arrangements of nerves of the spinal and sympathetic systems.
• noun In mathematics, a system of one-fold relations.
• noun The continuation of the prostatic plexus, supplying the erectile tissue of the penis. Also called cavernous nerves.
• noun Same as gastric plexus .
• noun A secondary plexus of the cæliac, accompanying the gastric artery. Also called coronary plexus.
• noun A large and copiously anastomosing network of veins in the lower wall of the rectum, beneath the mucous coat, from which the hemorrhoidal veins proceed.
• noun A plexus of veins surrounding the base of the prostate, formed mainly from the dorsal veins of the penis.
• noun The lower section of the sacral plexus .
• noun A plexus of veins in the back of the pelvis, tributary to the middle sacral vein.
• noun Same as pampiniform plexus.
• noun Venous channels at the sides of the uterus, and in the broad ligaments, emptying into the ovarian veins.
• noun A plexus derived from the pelvic plexus, distributed to the lower part and side of the bladder, the prostate, and the seminal vesicle.
• noun In botany, the mass of branched and anastomosing filaments of certain algæ.
• noun In physical geography, the irregular and complicated junction of a number of similar features, such as ridges, river channels, etc.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Anat.) A network of vessels, nerves, or fibers.
• noun (Math.) The system of equations required for the complete expression of the relations which exist between a set of quantities.
• noun A network; an intricate or interwoven combination of elements or parts in a coherent structure.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A network or interwoven mass, especially (anatomy) of nerves, blood vessels, or lymphatic vessels.
• noun mathematics The system of equations required for the complete expression of the relations which exist between a set of quantities.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a network of intersecting blood vessels or intersecting nerves or intersecting lymph vessels