UML

UML stands for Unified modeling language. it represents the standard modeling language language for system design. or uml is a visual language that lets you model process,software and system.
what is UML : The UML is made up of notation and diagrams.
Notations: Notation consists of the elements that work together in a diagram such as symbols,connections, notes ,values etc.
Diagrams: diagrams are pictorial representations of process the system or some part of it.

UML is a set of specifications created and distributed by the Object Management Group.
in this UML is defined in two parts.

infrastructure

superstructure

and two associated specifications

Diagram interchange

Object constraint language

see www.omg.org for more information.