Definitions

from The American Heritage® Dictionary of the English Language, 4th Edition

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

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A plant of the genus Ambrosia. These weeds are particularly noted for producing pollen which people with hay fever are allergic to.

from the GNU version of the Collaborative International Dictionary of English

  • n. A common American composite weed (Ambrosia artemisiæfolia) with finely divided leaves; hogweed.

from The Century Dictionary and Cyclopedia

  • n. Any plant of the composite genus Ambrosia; especially, the common North American species A. trifida, the great ragweed or horse-cane, and A. artemisiæfolia, the Roman wormwood or hogweed.
  • n. The ragwort or St.-James-wort, Senecio Jacobæa.

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

  • n. any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthma
  • n. widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity

Etymologies

From the ragged shape of its leaves.
(American Heritage® Dictionary of the English Language, Fourth Edition)
rag +‎ weed (Wiktionary)

Examples

  • If you're allergic to other plants, such as ragweed, your risk of an allergic reaction to Calendula may be greater.

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  • Old field plant communities are composed primarily of successional species such as ragweed, asters, goldenrod, sumac, wild carrot and various grasses.

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  • Cetirizine Hydrochloride syrup is indicated for the relief of symptoms associated with seasonal allergic rhinitis due to allergens such as ragweed, grass and tree pollens in adults and children 2 years of age and older.

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  • Those who have problems with weeds, such as ragweed, tend to suffer most mid-August to mid-September.

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  • In spring, for example, tree pollens make their presence felt most strongly during morning hours, whereas allergens such as ragweed tend to do their damage in the middle of the day during the fall season.

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  • Since response to allergens such as ragweed occurs quickly not only in the nose but also in the sinuses, "you can try treatment before exposure," he said.

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  • "The extreme change in humidity and temperature bring on a flurry of allergens such as ragweed, dust and mold."

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  • The fall brings new allergy triggers that are not prevalent in the spring, such as ragweed, according to the foundation.

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  • Laws, inserted by chapter 163 of the acts of 1949, is hereby etc'amende'd. amended by inserting after the word "ragweed" in lines 2 and 4, in each instance, the words: —, goldenrod and poison ivy, — so as to read as follows: — (36A) For acquiring information regarding the growth of amhorw fo?

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  • Tree season usually lasts from mid-February through April, grass season occurs from May to early July, and late summer brings weeds such as ragweed, which last until the first solid freeze.

    Kansan.com stories

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