In music, the bore of a wind instrument is its interior chamber. This defines a flow path through which air travels, which is set into vibration to produce sounds. The shape of the bore has a strong influence on the instrument's timbre.

The cornet is a brass instrument similar to the trumpet but distinguished from it by its conical bore, more compact shape, and mellower tone quality. The most common cornet is a transposing instrument in B♭. There is also a soprano cornet in E♭ and cornets in A and C. All are unrelated to the Renaissance and early Baroque cornett.