Register | Noun | \ˈre-jə-stər\ | The range of a human voice or a musical instrument. A higher register indicates a higher pitch. For example: a soprano sings in a higher register than a tenor. The register in which an instrument plays, or in which a part is written, affects the quality of sound or timbre. Register is also used structurally in musical form, with the climax of a piece usually being in the highest register of that piece.
Usage | “The clarinet has a distinctive smokey lower register, whereby its upper register is almost flute-like.”