<p><strong>Adjective</strong></p><ul><li>Apt or liable to vary or change; changeable: variable moods.</li><li>Antonyms: constant.</li><li>Capable of being varied or changed; alterable: a variable time limit for completion of a book.</li><li>Inconstant; fickle: a variable lover.</li><li>Synonyms: mercurial, unsteady, vacillating.</li><li>Antonyms: constant.</li><li>Having much variation or diversity.</li><li>Biology: deviating from the usual type, as a species or a specific character.</li><li>Astronomy: (of a star) changing in brightness.</li><li>Meteorology: (of wind) tending to change in direction.</li><li>Mathematics: having the nature or characteristics of a variable.</li></ul><p><strong>Noun</strong></p><ul><li>Something that may or does vary or change; a variable feature or factor.</li><li>Mathematics, Computers: a quantity or function that may assume any given value or set of values; a symbol that represents this.</li><li>Logic: (in the functional calculus) a symbol for an unspecified member of a class of things or statements. Compare bound variable, free variable.</li><li>Astronomy: variable star.</li><li>Meteorology: a shifting wind, especially as distinguished from a trade wind.</li></ul>