The Collaborative International Dictionary of English v.0.48:
Neutral \Neu"tral\, a. [L. neutralis, fr. neuter. See Neuter.]
1. Not engaged on either side; not taking part with or
assisting either of two or more contending parties;
The heart can not possibly remain neutral, but
constantly takes part one way or the other.
2. Neither good nor bad; of medium quality; middling; not
decided or pronounced.
Some things good, and some things ill, do seem,
And neutral some, in her fantastic eye. --Sir J.
3. (Biol.) Neuter. See Neuter, a., 3.
4. (Chem.) Having neither acid nor basic properties; unable
to turn red litmus blue or blue litmus red; -- said of
certain salts or other compounds. Contrasted with acid,
Neutral axis, Neutral surface (Mech.), that line or
plane, in a beam under transverse pressure, at which the
fibers are neither stretched nor compressed, or where the
longitudinal stress is zero. See Axis.
Neutral equilibrium (Mech.), the kind of equilibrium of a
body so placed that when moved slighty it neither tends to
return to its former position not depart more widely from
it, as a perfect sphere or cylinder on a horizontal plane.
Neutral salt (Chem.), a salt formed by the complete
replacement of the hydrogen in an acid or base; in the
former case by a positive or basic, in the latter by a
negative or acid, element or radical.
Neutral tint, a bluish gray pigment, used in water colors,
made by mixing indigo or other blue some warm color. the
shades vary greatly.
Neutral vowel, the vowel element having an obscure and
indefinite quality, such as is commonly taken by the vowel
in many unaccented syllables. It is regarded by some as
identical with the [u^] in up, and is called also the
natural vowel, as unformed by art and effort; it is also
called the indefinite vowel. It is symbolized in some
phonetic alphabets by the schwa ([schwa]). See Guide to
Pronunciation, [sect] 17.