Something that is variegated has various tones or colors; it can also mean filled with variety.
An invariable quantity is constant or unchanging.
A variant form of something differs from the normal state because it has changed in some way.
Something that is variable is likely to change often, usually when you don't expect it to.
A variety of things is a number of different objects in a group of similar objects, such as different kinds of soup or many colors of pens.
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