\E*lev"enth\, a. [Cf. AS. endlyfta. See {Eleven}.]
1. Next after the tenth; as, the eleventh chapter.
2. Constituting one of eleven parts into which a thing is
   divided; as, the eleventh part of a thing.
3. (Mus.) Of or pertaining to the interval of the octave and
   the fourth.

\E*lev"enth\, n.
1. The quotient of a unit divided by eleven; one of eleven
   equal parts.
2. (Mus.) The interval consisting of ten conjunct degrees;
   the interval made up of an octave and a fourth.