Webster's Revised Unabridged Dictionary · 1913

Turnkey

Turnkey (tûrn"kē`) , noun

1.
A person who has charge of the keys of a prison, for opening and fastening the doors; a warder.
2.
(Dentistry) An instrument with a hinged claw, -- used for extracting teeth with a twist.

turnkey (tûrn"kē`) , adjective

Of or pertaining to a building, complex device, system, or industrial installation which is sold by a contractor only after it is ready for immediate occupation or use; fully functional and ready for use; -- used of complex systems of a type which often require preparation or installation by the user before being capable of functioning as intended; as, a turnkey ethylene production plant; a turnkey apartment building.