(linguistics) The situation where two or more forms appear in the same environment without a change in meaning, and without either one being considered incorrect.

plural of variation selector

(computing, typography) A metacharacter in Unicode that selects one of a set of semantically equivalent glyphs.

plural of variation ratio

(immunology) The mechanism by which an infectious organism changes its surface proteins in favor of circumventing a host immune response.

A compass of delicate construction, used in observations on the variations of the needle.

plural of variation compass

(genetics) The variation of the number of copies (normally two) of a gene, or of sequences of DNA, in the genome of a specific individual; has been linked to some diseases