Astragalus \As*trag"a*lus\, n. [L. See {Astragal}.] 1. (Anat.) The ankle bone, or hock bone; the bone of the tarsus which articulates with the tibia at the ankle. [1913 Webster] 2. (Bot.) A genus of papilionaceous plants, of the tribe {Galege[ae]}, containing numerous species, two of which are called, in English, {milk vetch} and {licorice vetch}. {Gum tragacanth} is obtained from different oriental species, particularly the {Astragalus gummifer} and {Astragalus verus}. [1913 Webster] 3. (Arch.) See {Astragal}, 1. [1913 Webster]