Source : Webster's Revised Unabridged Dictionary (1913)

Moll \Moll\, a. [G., fr. L. mollis soft, tender, elegiac. Cf.
   {Molle}.] (Mus.)
   Minor; in the minor mode; as, A moll, that is, A minor.

Source : WordNet®

moll
     n : the girl friend of a gangster [syn: {gun moll}, {gangster's
         moll}]