1) Turnkey is a product or service that is designed, supplied, built, or installed fully complete and ready to operate. The term implies that the end user just has to turn a key and start using the product or service.
2) In training, a turnkey is a employee who has been sent somewhere to learn a specific skill. The turnkey is expected to return and share what they have learned with other employees. The turnkey becomes a trainer who turns the keys (of knowledge) over to someone else.