A whir is the soft, buzzing sound made by something spinning or moving rapidly. You hear it when a hummingbird's wings beat so fast they blur into motion, or when a computer fan spins up to cool the processor inside. A toy helicopter's rotors make a whirring sound as they slice through the air.

The word captures that particular quality of continuous, rapid movement: not a single whoosh or thump, but a steady whir, whir, whir. An old projector whirs as it plays a film. A bicycle wheel whirs when you flip the bike upside down and spin it with your hand. Even a deck of cards being shuffled quickly by an expert dealer can create a soft whirring noise.

As a verb, to whir means to make that sound or to move in a way that creates it. You might say the ceiling fan whirred quietly overhead, or that a flock of quail whirred into the sky when startled. The word itself almost sounds like what it describes, which makes it satisfying to say out loud.