Greenfield and Brownfield

 
A greenfield site is one to be used for housing or commerce, whose previous use (if any) was agricultural. The term can lso be used generally to refer to any undeveloped lands such as fields or forests. The term has been around for many decades.

It was only recently that I heard the term brownfield site. Brownfield sites iare abandoned or underused industrial and commercial facilities available for re-use. Expansion or redevelopment of such a facility may be complicated by real or perceived environmental contaminations.