Definition - What does Prism mean?
Mozilla Prism is an application platform allowing specific browser windows to run Web applications according to user requests.
The site-specific browser (SSB) model is considered the origin of the prism application, where an SSB based browser can only present information from a certain website or domain. SSB based browsers have the advantage of being non-redundant. Every button and tool suits the specified website exclusively and perfectly. A general purpose Web browser can serve a wide variety of websites and have a wide variety of tools to accommodate all of them.
Techopedia explains Prism
Prism has a great advantage because a user may open multiple tabs for websites with or without prism. If a prism-based website crashes, websites not depending on a prism application will not crash, avoiding loss of data and time.
An SSB based browser has an advantage when filling out a form. Typical website forms lose data when the back button is pressed. But an SSB based browser may be programmed to automatically save data when the back button is pressed. The saved data will automatically reappear when the user presses the forward button, saving the user time and effort.