Dashboard
"The default Dashboard will be the first page you see after logging in. (text from here)"
Posts
"By default, your homepage is your blog post page. Posts are dynamic information, usually displayed in reverse-chronological order with the most recent post at the top of the page. Common elements of a post include: title, published date, author information, content, comments, tags and categories. See the Working with Posts guide for details. (text from here)"
Pages
"Pages are static. They are a place for information you want to share with readers but don't expect to update frequently. For example, you might create an About, Contact or Rules and Guidelines page. Common elements of a page includes: title, content and comments. See the Working with Pages guide for details. We recommend limiting the number of Pages on your site, as too many pages can make information harder to find and manage. (text from here.)"