A Page is often used to present "static" information about yourself or your site. A good example of a Page is information you would place on an About Page. A Page should not be confused with the time-oriented objects called posts. Pages are typically "timeless" in nature and live "outside" your blog.

The word "page" has long been used to describe any HTML document on the web. In WordPress, however, "Page" refers to a very specific feature first introduced in WordPress version 1.5.

Reference http://codex.wordpress.org/Glossary