Related terms
A web node is a server hosting the PRPC portion of a Pega Composite application. Special configuration is required. Because the application may be accessed by a large community of users or directly from the World Wide web, PRPC can enforce special security and integrity restrictions.
Technically, a web node is a server node with "web" as the value of the nodetype entry in the prconfig.xml file or Dynamic System Settings.
See PDN article About Internet Application Composer.