leopard's bane \leop"ard's bane`\ (l[e^]p"[~e]rdz b[=a]n`) n. (Bot.) A name of several harmless plants, as {Arnica montana} ({Arnica acaulis} syn. {Doronicum acaule}), {Senecio Doronicum}, and {Paris quadrifolia}. Syn: leopardbane, leopard's-bane. [1913 Webster +PJC]