In real estate, turnkey refers to a house, apartment, business site, or other facility that is built so that a generic owner can start using it -- either by moving in, or through renting it out -- without further development. This is sometimes contrasted to build-to-order, but you can also have turnkey built-to-order facilities; the key feature is that in turnkey constructions the contractor is legally responsible for all aspects of the design, and the new owner should not have to make sufficient changes to shift this legal responsibility.