Posts and Pages Defined

From support.wordpress.com

Posts

Posts are entries listed in reverse chronological order on the blog home page (or on the posts page if you have set a different page to be the home page in the Settings/Reading area of the dashboard.) If you have created any sticky posts, those will appear before the other posts. Posts can be found in the Archives, Categories, Recent Posts, and other widgets. Posts are also displayed in the RSS feed of the blog.

If you want your posts to appear on a page other than your home page, see the Choose Settings tutorial.

See Create/Edit a Post for more detailed information.

Pages

Pages are static and are not listed by date. Pages do not use tags or categories. An About Me page is the classic example. Pages can be displayed in the sidebar using the Pages widget, or you can link to pages from the blog menu. Some themes display pages in tabs at the top of the blog. If you have an “About Me” page, you can place this on the menu. But if you want to have a submenu for pages that should fall under the About Me category, such as “Bio” and “CV,” you can give them a parent page of “About Me.”