Illustration of ragweed
: any of various chiefly North American weedy composite herbs (genus Ambrosia) that produce highly allergenic pollen
Examples of ragweed in a Sentence
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While anywhere that there is plant growth is susceptible to various pollens and ragweed, some cities and regions in the United States seem notoriously bad for allergy sufferers.
—
Laura Baisas, Popular Science, 10 Apr. 2025
Seasonal allergies occur when the immune system interprets certain airborne substances, like ragweed or tree pollen, as a threat and overreacts.
—Sarah Cottone, Health, 16 Apr. 2025
Our top allergens right now are ragweed, chenopods and elm.
—Megan Stringer, Axios, 16 Sep. 2024
In Europe, projections showed a probable increase in Ambrosia—or ragweed pollen—also linked to rising temperatures.
—Jeffrey Kluger, Time, 9 Apr. 2025
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Laura Baisas, Popular Science, 10 Apr. 2025
Seasonal allergies occur when the immune system interprets certain airborne substances, like ragweed or tree pollen, as a threat and overreacts.
—Sarah Cottone, Health, 16 Apr. 2025
Our top allergens right now are ragweed, chenopods and elm.
—Megan Stringer, Axios, 16 Sep. 2024
In Europe, projections showed a probable increase in Ambrosia—or ragweed pollen—also linked to rising temperatures.
—Jeffrey Kluger, Time, 9 Apr. 2025
See All Example Sentences for ragweed
Cite this Entry
“Ragweed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ragweed. Accessed 9 May. 2025.
Copy CitationKids Definition
ragweed
noun
rag·weed
ˈrag-ˌwēd 
: any of various chiefly North American weedy herbs related to the daisies and producing pollen irritating to the eyes and noses of some persons
Medical Definition
ragweed
noun
rag·weed
ˈrag-ˌwēd
: any of various chiefly North American weedy herbaceous plants comprising the genus Ambrosia and producing highly allergenic pollen responsible for much hay fever and asthma: as
a
: an annual weed (A. artemisiifolia) with finely divided foliage that is common on open or cultivated ground in much of North America
b
: a coarse annual (A. trifida) with some or all of the leaves usually deeply and palmately 3-cleft or 5-cleft
called also great ragweed
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