Unified Modeling Language

The Unified Modeling Language (UML} is a standard for diagramming program design and development.

The main types of diagrams that belong to UML are:

class diagrams --------- to show the relationships between objects and classes
                         In Detail + Examples
sequence diagrams ------ to show time dependency of information flow 
                         Example
collaboration diagrams - to show time dependency of information flow between objects
use case diagrams ------ to show a high level example of system functionality as it relates to 
                          information flow between a system and its users
state diagrams --------- to show how messages change the state of objects over time
                         Example
component diagrams ----- to show how objects are contained
deployment diagrams ---- to show time dependencies in deployment
entity relationship diagrams -

James Rumbaugh, Ivar Jacobson and Grady Booch are together considered the main contributors to UML historically. Together they formed Rational Software.