Swoosh is the soft rushing noise something makes when it moves fast through air or water — and also the word for that noise itself. As a verb: a car swooshes past, a skier swooshes down the hill, a long skirt swooshes as someone walks. As a noun: 'the swoosh of the doors', 'a swoosh of water'. The sound it names is smooth and continuous, not a bang or a crack; there is air in it. English has a small family of these sound-words — whoosh, swish, swoosh — and speakers use them loosely, so do not worry about a hard line between them. 'Swoosh' also names a shape: a curved mark that looks like the trace of something moving fast. The Nike tick is officially called the Swoosh, and designers now talk about 'a swoosh' on any logo with that swept curve. In basketball you may hear it for a ball dropping cleanly through the net.