Schema markup is code (semantic vocabulary) that you put on your website to help the search engines return more informative results for users. If you've ever used rich snippets, you'll understand exactly what schema markup is all about.

Schema markup, also known as structured data, is the language search engines use to read and understand the content on your pages. By language, we mean a semantic vocabulary (code) that helps search engines characterize and categorize the content of web pages.