Engineering, procurement, and construction (EPC) contracts are the most common form of contract used to undertake construction works by the private sector on large-scale and complex infrastructure projects. Under an EPC contract a contractor is obliged to deliver a complete facility to a developer who need only turn a key to start operating the facility, hence EPC contracts are sometimes called turnkey construction contracts
An EPC, LSTK, or EPCC are all same types of contract. This form of contract is covered by the FIDIC (International Federation of Consulting Engineers) Silver Book  containing the title words EPC/turnkey. The initials EPCM are also encountered frequently on international projects, but this is very different from EPC. EPCM is a services-only contract, under which the contractor performs engineering, procurement and construction management services. In an EPCM arrangement, the client selects a contractor who provides management services for the whole project on behalf of the client.
In the construction industry, EPC is an acronym for Engineering, Procurement and Construction in connection with projects such as tank terminals. It is a standard term that refers to a special form of project execution and contract design.