noun

1. a person, animal, or thing that works; specif., a person who is employed to do physical or mental work for wages, esp. in order to earn a living, as in a trade, industry, business, office, etc. or on a farm, ranch, etc.
2. a person who works for a cause, organization, etc. volunteer workers, a party worker
3. any of a class of sterile or sexually imperfect ants, bees, wasps, etc. that do work for the colony: with the exception of termites, workers are normally females
4. Printing an electrotype used to print from, as distinguished from one used as a mold for making duplicate electrotypes