A greenhouse (also glasshouse or, especially when artificially heated, hothouse) is a room or an entire freestanding building, designed to grow plants from an environment or climatic zone different to the one in which the gardener lives. Greenhouses maintain stable or controlled levels of light, temperature and humidity.
Greenhouses were originally used to grown temperate and tropical plants in cooler areas, but a variant called the shade house has developed in the tropics and subtropics for protecting temperate plants from too much sun.
Botanic gardens may have huge greenhouses for their collections: some can house banana trees and other very large specimens.
Specialised types of greenhouse and shadehouses: