plex·us (pl?k?s?s)n. pl. plexus or plex·us·es 1. A structure in the form of a network, especially of nerves, blood vessels, or lymphatics: the cardiac plexus; the pelvic plexus.2. A combination of interlaced parts; a network.[New Latin, from Latin, braid, from past participle of plectere, to plait; see plek- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.plexus (?pl?ks?s) n, pl -uses or -us1. (Anatomy) any complex network of nerves, blood vessels, or lymphatic vessels2. an intricate network or arrangement[C17: New Latin, from Latin plectere to braid, plait]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014plex?us (?pl?k s?s) n., pl. -us?es, -us. 1. a network, as of nerves or blood vessels. 2. any complex structure containing an intricate network of parts: the plexus of international relations. [1675?85;