Schema.org

A set of vocabulary that was created collaboratively by Google, Yahoo, Microsoft and Yandex to structure metadata (microdata) on web pages. This markup can help search engines understand content of a page and website for enhanced results on the SERP.

An example of microdata would be a website’s homepage having logo, organization, contact and social media markup for knowledge card results. There are three ways to implement Schema.org microdata on your site: HTML, RDFa and JSON-LD with JSON-LD being the most popular and recommended method.