Superius

In early vocal music, Superius is the Latin-derived name given to the highest voice-part. ...
Found on http://en.wikipedia.org/wiki/Superius

superius

(from the article `tenor`) ...century, tenor referred to the part `holding` the cantus firmus, the plainsong, or other melody on which a composition was usually built. The ...
Found on http://www.britannica.com/eb/a-z/s/188

superius

the top voice in a polyphonic texture; the term becomes common in the fifteenth century.
Found on http://people.vanderbilt.edu/~cynthia.cyrus/ORB/orbgloss.htm
No exact match found