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.