Source : Webster's Revised Unabridged Dictionary (1913)

Minor \Mi"nor\, a. [L., a comparative with no positive; akin to
   AS. min small, G. minder less, OHG. minniro, a., min, adv.,
   Icel. minni, a., minnr, adv., Goth. minniza, a., mins, adv.,
   Ir. & Gael. min small, tender, L. minuere to lessen, Gr. ?,
   Skr. mi to damage. Cf. {Minish}, {Minister}, {Minus},
   {Minute}.]
   1. Inferior in bulk, degree, importance, etc.; less; smaller;
      of little account; as, minor divisions of a body.

   2. (Mus.) Less by a semitone in interval or difference of
      pitch; as, a minor third.

   {Asia Minor} (Geog.), the Lesser Asia; that part of Asia
      which lies between the Euxine, or Black Sea, on the north,
      and the Mediterranean on the south.

   {Minor mode} (Mus.), that mode, or scale, in which the third
      and sixth are minor, -- much used for mournful and solemn
      subjects.

   {Minor orders} (Eccl.), the rank of persons employed in
      ecclesiastical offices who are not in holy orders, as
      doorkeepers, acolytes, etc.

   {Minor scale} (Mus.) The form of the minor scale is various.
      The strictly correct form has the third and sixth minor,
      with a semitone between the seventh and eighth, which
      involves an augmented second interval, or three semitones,
      between the sixth and seventh, as, ^{6/F}, ^{7/G[sharp]},
      ^{8/A}. But, for melodic purposes, both the sixth and the
      seventh are sometimes made major in the ascending, and
      minor in the descending, scale, thus:

Source : WordNet®

minor mode
     n : a key based on the minor scale [syn: {minor key}]