panther n.

mid-13c., panter, another name for the leopard, from Old French pantere "panther" (12c.) and directly from Latin panthera, from Greek panther "panther, leopard," probably of Oriental origin. An ancient folk-etymology derivation from Greek pan- "all" + thēr "beast" led to many curious fables. The word was applied to the American cougar or puma by 1730.