The tenor is a type of male singing voice and is the highest male voice within the modal register. The tenor voice (in choral music) lies between C3, the C one octave below middle C, and (A4), the A above middle C. In solo work, this range extends up to (C5), or "tenor high C." The low extreme for tenors is roughly B♭2 (two B♭s below middle C). At the highest extreme, some tenors can sing up to two Fs above middle C (F5).
Within opera, the lowest note in the standard tenor repertoire is A2 (Mime, Herod), but few roles fall below C3. The high extreme: a few tenor roles in the standard repertoire call for a "tenor C" (C5, one octave above middle C). Some (if not all) of the few top Cs in the standard operatic repertoire are either optional (such as in "Che gelida manina" in Puccini's La bohème) or interpolated (added) by tradition (such as in "Di quella pira" from Verdi's Il trovatore). Some operatic roles for tenor require a darker timbre and fewer high notes. In the leggero repertoire the highest note is an F5 (Arturo in "Credeasi, misera" from Bellini's I puritani), therefore, very few tenors can have this role in their repertoire. A shift in pitch since the mid 19th century means that the few written top Cs (such as in "Salut demeure" from Gounod's Faust) would have in fact demanded a note at least a semitone lower than today's standard pitch.
Within musical theatre, most tenor roles are written between B♭2 and A♭4, especially the romantic leads, although some fall as low as A♭2 and others as high as G5.