from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Something, such as a machine, that performs dependably under heavy or prolonged use: "the 50-year-old DC-3 ... one of aviation's most effective workhorses” ( Christian Science Monitor).
- n. A horse that is used for labor rather than for racing or riding.
- n. Informal A person who works tirelessly, especially at difficult or time-consuming tasks.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A horse used primarily for work; a draft horse
- n. Anyone or anything that does a lot of work; one who works consistently or regularly.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a horse used for plowing and hauling and other heavy labor
- n. machine that performs dependably under heavy use
work + horse (Wiktionary)