- any of several plants that secrete a milky juice or latex, especially those of the genus Asclepias, as A. syriaca.Compare milkweed family.
- any of various other plants having a milky juice, as certain spurges.
- Also called: silkweed any plant of the mostly North American genus Asclepias, having milky sap and pointed pods that split open to release tufted seeds: family AsclepiadaceaeSee also asclepias
- any of various other plants having milky sap
- orange milkweed another name for butterfly weed
- another name for monarch (def. 3)
n.1590s, from milk (n.) + weed (n.); used in reference to various plants whose juice resembles milk.