Something that is slightly different from a type or norm.

(genetics) A different sequence of a gene (locus).

(computing) A variable that can hold any of various unrelated data types.

(linguistics, lexicography) One of a set of words or other linguistic forms that conveys the same meaning or serves the same function.

Showing variety, diverse.

Showing deviation or disagreement.

(obsolete) Variable.

(programming) Covariant and/or contravariant.