adjective Ready to use without further assembly or test; supplied in a state that is ready to turn on and operate (typically refers to an assembly that is outsourced for manufacture).
They wanted a turnkey solution for the entire system, but we could only provide the enclosure.
noun A system that is supplied ready to switch on and operate.
noun A warder or jailer; a keeper of the keys in a prison.
verb To supply a turnkey product; to supply something fully assembled and ready to use.
We can sell you all the parts, or we can turnkey the entire unit.