Request is a type of scope. There are four types of scopes: Application, Session, Request, and PageContext. Attributes (aka variables) that are in application scope are shared across all threads in the servlet container. Similarly, attributes in session scope are shared across every request a specific user makes. Request scope attributes only live for the life of 1 request. Lastly, PageContext attributes only live during the rendering of a JSP page. All scopes are available anywhere in the presentation layer of your application, though PageContext is only available when you're inside a JSP.
Jon Emerson
http://www.jonemerson.net/
Difference between request and scope
