A collection of objects, each one representing a plugin that is embedded in the current page. The object being referred to is not the embedded data, but the plugin module that plays it.
Netscape and MSIE encapsulate plugin/embedded objects in a different way. In MSIE they are objects of the EMBED class. In Netscape they are objects commonly referred to as belonging to the Plugin class although they are really implemented as JavaObject objects. In MSIE, this is an ActiveX object.
There is additional confusion in that there is a plugins array that belongs to the document and another that belongs to the navigator object. They both contain collections of objects but of different types. This is further confused by the fact that the document.plugins array is another name for the document.embeds array.
Because of this confusing situation the best recommendation is that we refer to document.embeds and navigator.plugins and quietly ignore the document.plugins object. Furthermore we shall refer to Plugin objects as being something the browser can use to play embedded content and Embed objects will be an instance of a plugin that is alive and running in a document.
Beware of confusion between document.plugins and navigator.plugins. The former relates to the plugins currently used in the document while the latter lists the plugins currently available and supported by the browser.