horseweed has definitions from the field of botany
1
[ noun ] (botany) erect perennial strong-scented with serrate pointed leaves and a loose panicle of yellowish flowers; the eastern United States

Related terms

herb Collinsonia

2
[ noun ] (botany) common North American weed with linear leaves and small discoid heads of yellowish flowers; widely naturalized throughout temperate regions; sometimes placed in genus Erigeron

Related terms

weed Conyza

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