Your indexed website content in Sitecore Search
Before you can build search experiences, Sitecore Search needs to index your website content. After indexing is complete, you can view all your indexed, searchable content in Sitecore Search > Content Collection.
An indexed, searchable piece of content, such as a blog entry or a pair of shoes, is called an index document.
Every index document consists of attributes. Attributes are all the data that describes an index document. For example, index documents for blog entries might have attributes such as name, author, publication, and publication date. Index documents for shoes might have attributes such as name, description, brand, price, image URL, and stock status. You can view all attributes in Sitecore Search > Administration > Domain Settings > Attributes.
All index documents are grouped by entity. Depending on your implementation, index documents for blog entries might belong in the Content entity, and those for shoes might belong in the Product entity.
When you request content from Sitecore Search using widgets, you request index documents that belong to a specific entity, and you can configure whether to request all or only some of the attributes of those documents.