Greenfield is a type of deployment that refers to the installation of an IT system where previously there was none. This term is derived from the construction industry, where new development on previously undeveloped land is called greenfield development. Greenfield deployment may refer to a network, data center or other major IT projects when they are built from the ground up. This type of development is often beneficial because it is not subject to constraints posed by existing networks.
Greenfield networks may also be referred to as greenfield projects.
Source: Greenfield