Solr is an open-source search platform built on top of the Apache Lucene library. It is designed to provide powerful full-text search capabilities, allowing users to quickly find relevant information in large datasets. Solr supports various features like faceted search, filtering, and real-time indexing, making it suitable for applications that require efficient data retrieval. Developed by Apache Software Foundation, Solr is widely used in enterprise search applications, e-commerce sites, and content management systems. It can handle a variety of data formats, including text, XML, and JSON, and offers a robust API for integration with other systems.