1. an apparatus with rotating blades that creates a current of air for cooling or ventilation."a couple of ceiling fans, lazily turning"synonyms:air cooler, air conditioner, ventilator, blower, aerator; punkah "his living room had a couple of ceiling fans"a small sail for keeping the head of a windmill towards the wind.2. a handheld device, typically folding and shaped like a segment of a circle when spread out, that is waved so as to cool the person holding it."the girls were giggling behind their fans"