Source : Webster's Revised Unabridged Dictionary (1913)

   6. (Physiol.) The peculiar physical and mental character of
      an individual, in olden times erroneously supposed to be
      due to individual variation in the relations and
      proportions of the constituent parts of the body,
      especially of the fluids, as the bile, blood, lymph, etc.
      Hence the phrases, bilious or choleric temperament,
      sanguine temperament, etc., implying a predominance of one
      of these fluids and a corresponding influence on the
      temperament.

   {Equal temperament} (Mus.), that in which the variations from
      mathematically true pitch are distributed among all the
      keys alike.

   {Unequal temperament} (Mus.), that in which the variations
      are thrown into the keys least used.