Solr includes the specified file terms in an index. Indexing in Solr would be similar to creating an index at the end of a book that includes the words that appear in that book and their location, so basically we would take an inventory of the words that appear in the book and an inventory of the pages where said words appear That is, by including content in the index, we make said content available for search by Solr. This type of index, called an inverted index, is a way of structuring the information that will be retrieved by a search engine. You may find a longer answer of the way the information is stored and retrieved by solr in https://www.solr-tutorial.com/indexing-with-solr.html   ... View more