Polymorphism

In materials science polymorphism is the ability of a solid material to exist in more than one form or crystal structure. Diamond and graphite are examples of polymorphs of carbon. α-ferrite, austenite, and δ-ferrite are polymorphs of iron. When found in elemental solids the condition is also called Allotropy.

In biology multiple alleles of a gene within a population, usually expressing different phenotypes, are called polymorphism. For instance, human skin color is polymorphic.

In computer programming, type polymorphism is a way of writing functions or procedures that can operate on multiple types of objects.