1 machine that performs dependably under heavy use; "the IBM main frame computers have been the workhorse of the business world"
2 a horse used for plowing and hauling and other heavy labor
Moby Thesaurusbeast of burden, bidet, buck, carriage horse, cart horse, cavalry horse, draft horse, dray horse, driving horse, drudge, fag, fill horse, filler, galley slave, gigster, greasy grind, grind, grub, hack, hackney, horse, hunter, jument, lead, leader, mount, pack horse, palfrey, peon, plodder, plow horse, pole horse, polo pony, post-horse, remount, rider, riding horse, road horse, roadster, rouncy, saddle horse, saddler, sawbuck, shaft horse, slave, slavey, slogger, stalking-horse, sumpter, sumpter horse, swot, thill horse, thiller, toiler, trestle, wheeler, wheelhorse
- An expression that refers to the draft horse common in agricultural societies. The expression can refer to a machine, one that performs dependably under heavy, prolonged use, or a person, who works tirelessly at difficult, time-consuming tasks.