From UrbanCode website: 

"The Coarse Grained Session Bean idiom involves a stateless session bean that provides persistence services for a domain level concept such as items. That stateless session bean allows the client application to restore a particular instance of the domain level concept or to create a new instance of that concept or to update the representation of the concept instance in the persistent data store. The client application communicates with the stateless session bean in a coarse grained manner using state objects. 

http://www.urbancode.com/projects/ejbbenchmark/idioms.jsp

See Also UrbanCode, EjbBenchmark , EjbIdioms