Tenor
late Middle English: via Old French from medieval Latin, based on tenere ‘to hold’; so named because the tenor part was allotted (and therefore ‘held’) the melody.
wiktionary
From Middle English tenour, from Anglo-Norman tenour, from Old French tenor(“substance, contents, meaning, sense; tenor part in music”), from Latin tenor(“course, continuance; holder”), from teneō(“I hold”). In music, from the notion of the one who holds the melody, as opposed to the countertenor.
etymonline
tenor (n.)
c. 1300, "general meaning, prevailing course, purpose, drift," from Old French tenor "substance, contents, meaning, sense; tenor part in music" (13c. Modern French teneur), from Latin tenorem (nominative tenor) "a course," originally "continuance, uninterrupted course, a holding on," from tenere "to hold," from PIE root *ten- "to stretch." The musical sense of "high male voice" is attested from late 14c. in English, so-called because the sustained melody (canto fermo) was carried by the tenor's part. Meaning "singer with a tenor voice" is from late 15c. As an adjective in this sense from 1520s.
