音域是指某一乐器或人声歌唱所能发出的最低音到最高音之间的范围。

不同的乐器有高低宽窄不同的音域，较多数的乐器如管乐器、弦乐器在演奏音域边缘的声音时会比较困难，键盘乐器或打击乐器则较无这类问题，因此通常可以有较宽广的音域。

In music, tessitura (Italian: [tessiˈtuːra], texture; English /tɛsᵻˈtʊərə/) is the most musically acceptable and comfortable range for a given singer or, less frequently, musical instrument; the range in which a given type of voice presents its best-sounding texture or timbre. This broad definition is often interpreted to refer specifically to the pitch range that most frequently occurs within a given piece, or part, of music. For example, throughout the entirety of Wagner's Ring, the music written for the role of Siegfried ranges from C♯ to C, but the tessitura is described as high because the phrases are most often in the range of C to A.