Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
noun pl. guacos
any of several South American plants (genus Mikania of the composite family and genus Aristolochia of the birthwort family) used by the natives for asthma, snakebite, etc.
Origin: AmSp, probably from a Mayan language
Used by arrangement with John Wiley & Sons, Inc.