A greenhouse is normally characterized by the following:

* A building largely made up out of framing and glass panels
* A building that has been made economically and with an eye for keeping costs low. 
* A building which main purpose is the growing of and the caring for plants
* Often a free-standing building not attached to other types of buildings

This is in contrast with a [[conservatory]], a building that is often confused with a greenhouse as the main purpose of a conservatory is to be used as a living space, with plants sometimes intermixed.

A few examples of a greenhouse are the following:

* A large building on a farm filled with rows and rows of plants being grown for consumption or sale.
* A small building in a private garden or "allotment garden":[https://en.wikipedia.org/wiki/Allotment_(gardening)] used mainly for the growing of plants.
* A building that is of the same type of either of the two described above but is empty or used for the storage of other objects is still a greenhouse as well.
* A botanical garden can also be called a greenhouse although it often overlaps with a conservatory.