noun

• The ability to assume different forms or shapes.
• (biology) The coexistence, in the same locality, of two or more distinct forms independent of sex, not connected by intermediate gradations, but produced from common parents.
• (object-oriented programming) The feature pertaining to the dynamic treatment of data elements based on their type, allowing for an instance of a method to have several definitions.
• (mathematics, type theory) The property of certain typed formal systems of allowing for the use of type variables and binders/quantifiers over those type variables; likewise, the property of certain expressions (within such typed formal systems) of making use of at least one such typed variable.
• (crystallography) The ability of a solid material to exist in more than one form or crystal structure; pleomorphism.
• (genetics) The regular existence of two or more different genotypes within a given species or population; also, variability of amino acid sequences within a gene's protein.