data are those that are organized into semantic blocks of relationships within the same group. They have the same descriptions (attributes), classes within a group, and share the same format (schema).

Structured data is another way of saying "connected" or "systematized" data (as opposed to unconnected or unsystematized).

Schema.org example , by labeling it with additional information that helps search understand it.

What is structured data?

In the context of Search Engine Optimization ( SEO), structured data is fundamental for algorithms to understand content that humans can easily comprehend. In a scenario where machines learn, computers need us professionals to use standards like Schema.org to make sense of website content.