brownfield adjective 1noun 1forms 1 adjective1 •Being a development that has to integrate with legacy systems.Brownfield development is probably the most common situation for developers to be in, and in order for business to continue, an existing application infrastructure is necessary. — 2014 noun[before a noun]1 •A site, to be used for housing or commerce, that has been previously used for industry and may be contaminated or need extensive clearing.My budget will improve our environment by accelerating the cleanup of toxic brownfields. — 2001 formsbrownfields