Ambitus

Webster's Dictionary

(1): (n.) The exterior edge or border of a thing, as the border of a leaf, or the outline of a bivalve shell.

(2): (n.) A canvassing for votes.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature

(compass in music). In the earliest Church melodies, the compass did not in some instances reach, and in few did it exceed, a fifth. In Gregorian music the octave was the limit, but in later times this compass was much extended. A melody occupying or employing its whole compass was called cantus perfectus; falling short of this, cantus imperfectus; exceeding it, cantus plusquamperfectus. Subsequently other interpretations have been given to the word ambitus.