Va`ri*a"tion (?), n. [OE. variatioun,
F. variation, L. variatio. See Vary.]
1. The act of varying; a partial change in the
form, position, state, or qualities of a thing; modification; alternation;
mutation; diversity; deviation; as, a variation of color in
different lights; a variation in size; variation of
The essences of things are conceived not capable of any such
2. Extent to which a thing varies; amount of
departure from a position or state; amount or rate of change.
3. (Gram.) Change of termination of words,
as in declension, conjugation, derivation, etc.
4. (Mus.) Repetition of a theme or melody
with fanciful embellishments or modifications, in time, tune, or harmony,
or sometimes change of key; the presentation of a musical thought in new
and varied aspects, yet so that the essential features of the original
shall still preserve their identity.
5. (Alg.) One of the different arrangements
which can be made of any number of quantities taking a certain number of
Annual variation (Astron.), the yearly
change in the right ascension or declination of a star, produced by the
combined effects of the precession of the equinoxes and the proper motion
of the star. -- Calculus of variations. See
under Calculus. -- Variation compass. See
under Compass. -- Variation of the moon
(Astron.), an inequality of the moon's motion, depending on the
angular distance of the moon from the sun. It is greater at the octants,
and zero at the quadratures. -- Variation of the
needle (Geog. & Naut.), the angle included between the
true and magnetic meridians of a place; the deviation of the direction of a
magnetic needle from the true north and south line; -- called also
declination of the needle.
Syn. -- Change; vicissitude; variety; deviation.