What's the difference between i.e. and e.g.?
c.1300, "general meaning, purpose, drift," from Old French tenour "substance, sense" (13c.), from Latin tenorem (nominative tenor) "contents, course," originally "a holding on," from tenere "to hold" (see tenet). The musical sense of "high male voice" is attested from late 14c., because the sustained melody (canto fermo) was carried by the tenor's part.