Clack

Clack is a short, sharp, abrupt sound produced when two hard surfaces strike or rub against each other, or when a mechanism moves in a brisk, percussive way. The term is largely onomatopoeic, conveying the instantaneous, hollow character of the noise. In usage, clack functions as both a noun and a verb.

As a noun, clack refers to the sound itself, such as the clack of typewriter keys, the clack of hooves on cobblestones, or the rhythmic clack of a train on tracks. It can also describe a mechanism or device that generates such a sound, though this sense is more specialized and context-dependent.

As a verb, clack means to produce or cause a clack, as in a machine or tool whose actions emit a sharp, knocking sound. For example, a typewriter keys clacked as someone typed, or hooves clacked on a hard surface. In some dialect or literary uses, clack can also mean to talk noisily or briskly, though this sense is less common in modern standard English.

Clack is used across descriptive contexts—from technical descriptions of machinery to everyday narration—where the focal point is a quick, hollow, or metallic sound. It is distinct from related terms such as click, clink, or bang by emphasizing a short, forceful impact or a rapid sequence of strikes.