lo·co·weed (lō'kō-wēd') n. Any of several plants of the genera Oxytropis and Astragalus in the pea family, which are widespread in the western and central United States and cause severe poisoning when eaten by livestock. Also called crazyweed, loco1.
Main Entry: lo·co·weed Pronunciation: 'lO-(")kO-"wEd Function: noun : any of several leguminous plants (genera Astragalus andOxytropis) of western No. America that cause locoism in livestock