A profile in the Unified Modeling Language provides a generic extension mechanism for building UML models in particular domains. Profiles are based on additional stereotypes and tagged values that are applied to elements, attributes, methods, links, and link ends. A profile is a collection of such extensions and restrictions that together describe some particular modeling problem and facilitate modeling constructs in that domain. UML profiles tailor the language to specific areas: business modeling and others.
Examples
For example, the UML Profile for XML is defined by David Carlson in the book "Modeling XML Applications with UML" pp. 310 and describes a set of extensions to basic UML model elements to enable accurate modeling of XSD schemas. SysML is an OMG-standardized profile of UML for the purpose of performing system engineering.
