Eleventh \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.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Eleventh \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.

Source: Webster's Revised Unabridged Dictionary (1913)