Definition: When you are using frames or iframes then a relationship exists between the various pages that make up what is being displayed on the screen. Where one page contains another that page is the parent of the other page. This is not a reserved word so you can declare your own variable or function called parent but if you do then you will not be able to reference the parent page from within a page contained within a frame.
Examples:
parent.location.href = 'index.html';
