leash \'le-sh\ n [ME lees, leshe, fr. OF laisse, fr. laissier] 1: a line for leading or restraining an animal 2a: a set of three animals (as greyhounds, foxes, bucks, or hares) 2b: a set of three - leash vt 3: a Windows program developed at MIT to manage a user's Kerberos tickets.