Floatation is a British spelling of flotation. They sound the same and mean the same thing. The idea is floating: staying on water, or helping something stay on water. That core sense then goes out into real jobs. In science and swimming, flotation is the power to float, or a jacket that holds you up. In mining, flotation is a way to pull useful bits of rock away from waste: crushed rock goes into water with bubbles, and the useful bits ride the bubbles up. In British business English, a company's flotation is the day it first sells shares to the public; American English usually says going public, or IPO. Spas often write floatation tank for a dark, salty tank you lie still in — and they like this spelling with float still visible. The spelling flotation is what most people actually type, even in Britain. Neither spelling changes the meaning; floatation just keeps the word float easier to see.

英式拼法，等於 flotation。用法不同詞就不同：漂浮／浮力；礦業說「浮選」；公司第一次把股票賣給大眾，臺灣說「上市」、「掛牌」；漂浮艙也常寫成 floatation tank。