contractor

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One that agrees to furnish materials or perform services at a specified price, especially for construction work.
2. n. Something, especially a muscle, that contracts.

Century Dictionary and Cyclopedia

1. n. One who contracts; one of the parties to a contract, bargain, or agreement; one who covenants with another to do or to refrain from doing a particular thing.
2. n. Specifically One who contracts or covenants, either with a government or other public body or with private parties, to furnish supplies, or to construct works or erect buildings, or to perform any work or service, at a certain price or rate: as, a paving-contractor; a labor-contractor.
3. n. A muscle which contracts or lessens the size of a part; a constrictor.

Wiktionary

1. n. A person who executes the building or improving of buildings.
2. n. A person or company that performs specific tasks like electrical or plumbing work in construction projects.
3. n. A person or company hired to maintain existing facilities like air conditioning systems, groundskeeping, etc.

GNU Webster's 1913

1. n. One who contracts; one of the parties to a bargain; one who covenants to do anything for another; specifically, one who contracts to perform work on a rather large scale, at a certain price or rate, as in building houses or making a railroad.

WordNet 3.0

1. n. someone (a person or firm) who contracts to build things
2. n. a bodily organ that contracts
3. n. (law) a party to a contract
4. n. the bridge player in contract bridge who wins the bidding and can declare which suit is to be trumps