ragweed has definitions from the field of botany
1
[ noun ] (botany) widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity

Related terms

weed Senecio

2
[ noun ] (botany) any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthma

Synonyms

bitterweed ambrosia

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