1. A superabundance; an excess.
2. An excess of blood in the circulatory system or in one organ or area.

[Late Latin plēthōra, from Greek, from plēthein, to be full.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.