Home › Words › P › polyhousepolyhousepolyhouse means A polytunnel; a greenhouse or tunnel made of polyethylene, used to grow plants that require a higher temperature and/or humidity.EtymologyShort for polythene house.nounA polytunnel; a greenhouse or tunnel made of polyethylene, used to grow plants that require a higher temperature and/or humidity.Definitions & examples from Wiktionary (CC BY-SA 3.0).