9 letters · 16 points in Scrabble
noun erect perennial strong-scented with serrate pointed leaves and a loose panicle of yellowish flowers; the eastern United States
noun common North American weed with linear leaves and small discoid heads of yellowish flowers; widely naturalized throughout temperate regions; sometimes placed in genus Erigeron
originFrom horse + weed.
Etymology from Wiktionary, CC BY-SA 3.0