A weblog or blog is a website that originally was used like an online journal, but the power of that style of site was quickly realised by internet marketers and others and is now used to create millions of websites.

The general idea is that when you add a new article or content, this will show as the latest in a list of all your posts.

As Wordpress evolved it got more flexible in how these posts can be used. So now, you can list them like that, or split them up into categories, or via tags. With the help of plugins and code you can even make them do all sorts of other things like appear in a backward order, always show at the top or have customised posts for speciality sites.