sub·con·tract /ˌsəb-'kän-ˌtrakt/ n: a contract between a party to an original contract and a third party that assigns part of the performance (as building a house) of the original contract to the third partysubcontract /ˌsəb-'kän-ˌtrakt, -kən-'trakt/ vb
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.
the contract between a party and a main contractor who himself is contracted to another, often called the employer, albeit the contract is not one of employment in the contemporary colloquial sense. Subcontracts are very commonly found in building contracts. The employer contracts with the main contractor, who himself contracts for work to be done, like windows or floors, by others who can do so better or cheaper. A subcontractor may be nominated by the employer. There are effectively and legally only two contracts, the subcontractor not being contractually bound to the employer. Standard forms govern many of the relationships between the parties. In one case it was held that a subcontractor could be held liable to an employer in tort or delict where the relationship was proximate, indeed, very like contract: Junior Books v. The Veitchi Company 1982 SLT 492, a decision that although doubted has not been overruled and has been followed elsewhere in the Commonwealth. In the case of carriage by air, the provisions of the Warsaw Convention are extended to situations where the carrier has subcontracted business to another carrier to perform the whole or part of a carriage so that the goods are being carried by a carrier who has no direct contractual relationship with the owner.
Collins dictionary of law. W. J. Stewart. 2001.