The Collaborative International Dictionary of English v.0.48:
Temperament \Tem"per*a*ment\, n. [L. temperamentum a mixing in
due proportion, proper measure, temperament: cf. F.
temp['e]rament. See Temper, v. t.]
1. Internal constitution; state with respect to the relative
proportion of different qualities, or constituent parts.
The common law . . . has reduced the kingdom to its
just state and temperament. --Sir M. Hale.
2. Due mixture of qualities; a condition brought about by
mutual compromises or concessions. [Obs.]
However, I forejudge not any probable expedient, any
temperament that can be found in things of this
nature, so disputable on their side. --Milton.
3. The act of tempering or modifying; adjustment, as of
clashing rules, interests, passions, or the like; also,
the means by which such adjustment is effected.
Wholesome temperaments of the rashness of popular
assemblies. --Sir J.
4. Condition with regard to heat or cold; temperature. [Obs.]
Bodies are denominated "hot" and "cold" in
proportion to the present temperament of that part
of our body to which they are applied. --Locke.
5. (Mus.) A system of compromises in the tuning of organs,
pianofortes, and the like, whereby the tones generated
with the vibrations of a ground tone are mutually modified
and in part canceled, until their number reduced to the
actual practicable scale of twelve tones to the octave.
This scale, although in so far artificial, is yet closely
suggestive of its origin in nature, and this system of
tuning, although not mathematically true, yet satisfies
the ear, while it has the convenience that the same twelve
fixed tones answer for every key or scale, C[sharp]
becoming identical with D[flat], and so on.
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
Equal temperament (Mus.), that in which the variations from
mathematically true pitch are distributed among all the
Unequal temperament (Mus.), that in which the variations
are thrown into the keys least used.