Lucene (Apache Lucene)

Apache Lucene is an open-source search engine library that enables efficient and fast text search capabilities within applications. It indexes large volumes of data, such as documents or web pages, by breaking down the content into searchable terms. When a user submits a query, Lucene quickly retrieves relevant results by searching its index instead of scanning all the data. It's widely used in various systems, including websites, enterprise applications, and data management tools, to provide accurate, real-time search functionality. Essentially, it helps computers understand and find information quickly, much like a powerful, customizable search engine.