A profile defines limited extensions to a reference metamodel with the purpose of adapting the metamodel to a specific platform or domain.

A Profile is a kind of Package that extends a reference model. The primary extension construct is the Stereotypes, which are defined as part of Profiles.

A profile introduces several constraints, or restrictions, on ordinary metamodeling through the use of metaclasses.

A profile is a restricted form of a metamodel that must always be related to a reference metamodel, such as UML. A profile cannot be used without its reference metamodel, and defines a limited capability to extend metaclasses of the reference metamodel. The extensions are defined as stereotypes that apply to existing metaclasses.