Dobbin is an old-fashioned nickname for a farm horse, especially one that's plodding and patient. As workhorses, so-called dobbins performed heavy labor in the family fields, such as hauling or plowing. In Shakespeare's The Merchant of Venice, Launcelot encounters his blind father after many years apart: Launcelot: Pray you, let's have no more fooling about it, but give me your blessing; I am Launcelot, your boy that was, your son that is, your child that shall be. . . . and I am sure Margery your wife is my mother. Gobbo: Her name is Margery, indeed: I'll be sworn, if thou be Launcelot, thou art mine own flesh and blood. Lord worshipped might he be, what a beard hast thou got! Thou hast got more hair on thy chin than Dobbin my thill-horse has on his tail.