whir

Whir is a noun describing a low, continuous, rapidly repeating sound produced by mechanical devices in operation. It is often heard as a quiet but persistent hum or buzz, typically accompanied by the rapid motion of gears, turbines, or fans. The related verb whir (also spelled whirr) means to emit such a sound or to move with a rapid rotating motion, as in a computer fan whirring to life.

Etymology: The term is onomatopoeic, imitating the audible effect of rotating machinery. The spelling whirr is a common variant; both forms are found in English usage, with whirr more common in informal contexts.

Usage: Whir is used in technical descriptions to convey the auditory signature of devices in operation, for example the whir of a hard drive, the whir of a turbine, or the background whir of a ventilation system. It can also appear in literary writing to evoke a scene of activity or momentum, and in journalism to convey sensory detail.

Related terms: buzz, hum, murmur, sizzle. Onomatopoeia for machine sounds; this term sits within the broader category of acoustic phenomena and mechanical noise.