A Portakabin is a small building you can put up quickly and later move by truck — a temporary office, classroom, or site hut. It is a British brand name that many people in the UK use for any boxy portable cabin, the way some people say Hoover for any vacuum cleaner. Though actually, it is still a trademark, so careful writing may say portable cabin instead. The thing itself is usually a flat-roofed box that sits on the ground, not a tent. You see them on building sites and in school yards when a school needs extra rooms. American English is more likely to say portable classroom or trailer; many Americans have never heard Portakabin. In Taiwan the same kind of building is what people call a 組合屋.

組合屋、活動屋（英國廠牌名，常被當通稱）