Definition of greenhouses:
(n) :
A building used to grow plants, particularly one with large glass windows or plastic sheeting to trap heat from sunlight even in intemperate seasons or climates.
(v) :
(transitive) To place (plants) in a greenhouse.
(v) :
(transitive, figurative) To nurture in order to promote growth.
(n) :
(UK military slang, dated) The glass of a plane's cockpit.
(n) :
(medicine) A structure that shields the operating table to protect against bacteria.
(n) :
(climatology) A hot state in global climate.