SynonymDefinitionAntonym.com - English Synonym Dictionary

A quantity that can assume any of a set of values

A symbol (like x or y) that is used in mathematical or logical expressions to represent a variable quantity

Something that is likely to vary; something that is subject to variation

A star that varies noticeably in brightness

Liable to or capable of change

(used of a device) designed so that a property (as e.g. light) can be varied

Marked by diversity or difference