The Collaborative International Dictionary
Great ragweed
Ragweed \Rag"weed`\ (r[a^]g"w[=e]d`), n. (Bot.) A common American composite weed ( Ambrosia artemisi[ae]folia) with finely divided leaves; hogweed.
Great ragweed, a coarse American herb ( Ambrosia trifida), with rough three-lobed opposite leaves.
WordNet
great ragweed
n. a coarse annual with some leaves deeply and palmately 3-cleft or 5-cleft [syn: Ambrosia trifida]