Meta tags are descriptive tags that describe data. They don’t usually appear on the page itself (though some do). They are, however, machine readable and, historically, search engines have used the information in their listings.
If you look at your page’s source code you’ll see some meta tags between the
<!-- platinum seo pack 1.2.6 -->
and
<!-- /platinum one seo pack -->
The tags that you add when writing a post are markup tags and describe how your data should be displayed.
Some search engines also use the markup to weight content. A word between <h1></h1> tags is considered more important than words contained between regular <p></p> tags, which is why SEO types usually emphasise the importance of putting your keywords in headings, and bolding them within content.
I suppose in that way, it does blur the lines a little but, technically, it should be:
meta tags – describe the data
markup tags – display the data