an alphabetical list of words relating to a specific subject, text, or dialect.
Structured data is an on-page markup that helps search engines to better understand the content on the page and use the highlighted information to improve the business search results.
This can be seen below the website URL and meta description as an additional info in search results. For example, if you are searching for a restaurant in Delhi, you will see not only the restaurant’s name, but also additional information such as operation hours, pricing, reviews, availability and image. Also, if you have marked social profiles that can be highlighted in knowledge graphs. Few of the most common data fields include hotel reviews, blog posts, NAP.
Important markup formats are -
Content makred online with structured data are eligible to appear in more than one category of Google Search - Natural results, maps, answer box, news.
Do not use these terms interchangeably - Structured Data, Schema and Rich Snippets.
Structured Data: Structured data is a method of tagging web page content to remove ambiguity and help search engines understand the data much better.
Schema: Schema is a mark-up vocabulary listed at Schema.org used for creating structured data, which has provided a set of named attributes for various real-life objects. For example, here is the blog post object.
The structured data is made available to search engines by adding HTML mark-up.