Here's a link to info on using iframes. Beware of accessibility issues though among other things, and in no way are Iframes good to use gratuitiously ...
Iframes display a web page within another - in the same way that a web page might display an image ... Here's one, by default it displays the Bath Spa University library catalogue - it's a web page so it's fully functional:
You can target the frame to load other pages from links as follows:
All before you, in this world, is smoke and shadows.All before you, in this world, is smoke and shadows.
Words found on a door lintel in the garden of a house in the Cretan village of Argiroupolis.
The lintel is a fragment from the city state Lappa, which occupied the same site.
Fifteen hundred years later, when you use the web, from time to time you might well feel that the author was on to something. And if you work with particle physics, you'll know he was ...