Think of a tenor as a tone — in music, it's the range between baritone and alto in the human voice or in an instrument such as a tenor saxophone. It also is the "tone" or meaning of a spoken comment.
The meaning of the Latin word tenere, was "to hold to a course." Then the Old French took the word tenour in the 14th Century, giving it the meaning of “sense,” or a general feeling of a comment. But that same century, the original meaning resurfaced when the word entered the musical lexicon as the Italian tenore, or tenor, the name given to the high male voice because that was the voice that carried, or “held on to” the melody.