Also found in: Thesaurus, Medical, Idioms, Encyclopedia, Wikipedia.


1. Any of various weeds of the genus Ambrosia of the composite family, having small, greenish, unisexual flower heads and producing abundant pollen that is one of the chief causes of hay fever.
2. Chiefly British Ragwort.

[From the ragged shape of its leaves.]
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.


(Plants) any plant of the chiefly North American genus Ambrosia, such as A. artemisiifolia (common ragweed): family Asteraceae (composites). Their green tassel-like flowers produce large amounts of pollen, which causes hay fever. Also called: ambrosia
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014



any of the composite plants of the genus Ambrosia, the airborne pollen of which is the most prevalent cause of autumnal hay fever.
[1650–60; so called from its ragged appearance]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.ragweed - widespread European weed having yellow daisylike flowersragweed - widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity
genus Senecio, Senecio - enormous and diverse cosmopolitan genus of trees and shrubs and vines and herbs including many weeds
weed - any plant that crowds out cultivated plants
2.ragweed - any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthmaragweed - any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthma
genus Ambrosia - comprising the ragweeds; in some classification considered the type genus of a separate family Ambrosiaceae
Ambrosia artemisiifolia, common ragweed - annual weed with finely divided foliage and spikes of green flowers; common in North America; introduced elsewhere accidentally
Ambrosia trifida, great ragweed - a coarse annual with some leaves deeply and palmately three-cleft or five-cleft
Ambrosia psilostachya, perennial ragweed, western ragweed - coarse perennial ragweed with creeping roots of dry barren lands of southwestern United States and Mexico
weed - any plant that crowds out cultivated plants
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


[ˈrægwiːd] Nambrosía f
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005


n (bot) ambrosía
English-Spanish/Spanish-English Medical Dictionary Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
References in periodicals archive ?
Tree pollination occurs in the early part of the year, followed by grass pollination in spring and early summer and ragweed in the late summer and early autumn months.
Estimates of Common Ragweed Pollen Production for Urban Ragweed Plants.
According to the American College of Allergy, Asthma & Immunology, ragweed is one of the more common triggers of autumnal allergies.
Seeds of common ragweed were sown in soil in an unheated greenhouse at the Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha, China (25.354947[degrees]N, 114.56111[degrees]E).
There have been a few guesses, from ragweed to wild parsley, but no one can be sure.
The company said SHIELDEX 400SC controls a wide range of broadleaf and grass weeds, including troublesome weed, tall waterhemp, Palmer amaranth, giant ragweed and giant foxtail.
Many people regard spring as the prime pollen season, but one type reaches peak levels during the early fall: ragweed, a flower that can cause allergic rhinitis, also called hay fever, which affects approximately 23,000,000 people in the U.S., points out Blueair AB, an international indoor air cleaning technology company.
Unhealthy levels of smog and ragweed pollen, which are results of climate change, have put millions of people at risk of irritated eyes, noses, and lungs, a recent study said.
(1) While SLIT has been used outside the United States for decades, the US Food and Drug Administration (FDA) has recently approved 4 SLIT allergen extract products (tablets) for treatment of the symptoms and morbidity associated with grass pollen, ragweed, or house dust mite AR, with or without conjunctivitis.
(1) In this issue of EHP, scientists estimate how changing growth trends in ragweed may affect future pollen allergies in Europe, where the plant is a nonnative invasive weed.
M2 PHARMA-February 16, 2017-ALK's registration application for ragweed SLIT-tablet in Europe accepted for review