[syn: ragweed, ambrosia, bitterweed]
The Collaborative International Dictionary of English v.0.48:
Ragweed \Rag"weed`\ (r[a^]g"w[=e]d`), n. (Bot.)
A common American composite weed (Ambrosia artemisiaefolia)
with finely divided leaves; hogweed.
[1913 Webster]
Great ragweed, a coarse American herb (Ambrosia trifida),
with rough three-lobed opposite leaves.
[1913 Webster]
WordNet (r) 3.0 (2006):
ragweed
n 1: widespread European weed having yellow daisylike flowers;
sometimes an obnoxious weed and toxic to cattle if consumed
in quantity [syn: ragwort, tansy ragwort, ragweed,
benweed, Senecio jacobaea]
2: any of numerous chiefly North American weedy plants
constituting the genus Ambrosia that produce highly
allergenic pollen responsible for much hay fever and asthma
[syn: ragweed, ambrosia, bitterweed]