1911 Encyclopædia Britannica/Tenor
TENOR (through Fr. and It. from Lat. tenor, holding on, course, sense of a law, tone), a general course or direction, the drift or general meaning of a statement or discourse, hence, in law, the true purport and effect of a deed or instrument. The most general use of the word is, in music, for the highest kind of the natural adult male voice. This use descends from the Medieval Latin tenor, which was applied first to the chief melody, the cantus firmus, and then to the male voice to which the singing of this was assigned.