A Portakabin is a relocatable, stackable temporary building, most often used as site offices on a building site, or anywhere else where constructing an office is not practical or is pointless.
The name Portakabin is a trademark of Portakabin, Ltd., but is under threat of becoming a genericized trademark. It is frequently used to refer to temporary buildings made by other companies, although Portakabin Ltd actively discourage this use. The company is possibly better known for its invention of the Portaloo.
A number of specialised uses for Portakabins exist, including the Portakabin WardSpace, a fully fitted out hospital which can be assembled on-site in a matter of days.