What is timbre in music?

Timbre is defined as the unique quality or color of sound that distinguishes one musical instrument or voice from another, even when they are producing the same pitch or playing the same note. This characteristic is what allows us to differentiate between, for example, a piano and a violin playing the same melody. Timbre encompasses various aspects of sound, including the harmonic content, texture, and even the way an instrument is played, making it a crucial element in the overall experience of music.

The other options address different musical concepts that do not relate to timbre; loudness pertains to dynamics, tempo refers to the speed of the music, and style or genre involves the categorization of music based on characteristics such as instrumentation and form, none of which conveys the specific quality of sound that timbre does.