External Entity

• External entities are people, places, or things which interact with the application. 
• Usually, we identify titles/roles (e.g.,  Customer), departments (e.g., Accounts Receivable), organizations (e.g., Medicare Administration), or applications (e.g.,  Accounts Receivable Application) as entities. 
• The phrase 'interact with the application'  has a very specific meaning.  
• The entity is  outside the control and/or processing being modeled for the  current application.  That is,  external entity processing, procedures, and data are not subject to analysis or change. 
• Relationships between external entities are  not shown on the diagram(s) (i.e., external entities cannot connect to  each other).
• if you are modeling an  order processing application that does not do inventory control, the warehouse would be on the context diagram.  
• If inventory  control  and  warehouse  processing  are within the scope of the application, the warehouse would not be on the context diagram

Dictionary of External Entity

• Entity Name
• Aliases
• Definition
• Relationship to Application
• Contact, if entity is an organization

Sumber: Conger, 2008