From the Greek noun σίφων (síphōn), meaning "tube, pipe," as well as specifically referring to the device used for drawing wine out of a cask, the word siphon is both a verb and a noun in English. As a verb, it means "to convey, draw off, or empty using a siphon." And as a noun, a siphon is technically "a tube bent to form two legs of unequal length by which a liquid can be transferred to a lower level over an intermediate elevation by the pressure of the atmosphere in forcing the liquid up the shorter branch of the tube immersed in it while the excess of weight of the liquid in the longer branch when once filled causes a continuous flow." Essentially, even in antiquity, people figured out that differences in air pressure inside tubes, whether using suction through a straw, or simply using the open air of the atmosphere and different elevations could cause fluids to move through tubes easily. And they called this tube a siphon.