What is a green field hospital?

The term green field was originally used in

construction and development to reference new land that has never

been used where there was no need to demolish existing structures.

Nowadays, the term; greenfield project is used in many industries,

including software development and public works; where it means to

start a project without the need to consider any prior work.

So a green field hospital or museum or public

space can be deigned without limitation, it can use modern

ideas.