workhorse

noun

1. A horse used primarily for manual labor; a draft horse.

2. Anyone or anything that does a lot of work; something or someone who works consistently or regularly.

   “Those old machines are not very glamorous, but even 20 years after their introduction, they are still the workhorses of the industry.”

3. Machine that performs dependably under heavy use

   “the IBM main frame computers have been the workhorse of the business world”

4. A horse used for plowing and hauling and other heavy laboranimal