Elasticsearch is a powerful open-source search and analytics engine. It's known for its speed, scalability, and ability to handle a wide variety of use cases, such as log analytics, real-time application monitoring, and full-text search. Built on Apache Lucene, Elasticsearch allows for storing, searching, and analyzing large volumes of data quickly and in near real-time. It is a core component of the Elastic Stack (formerly known as ELK Stack, alongside Kibana and Logstash), providing an integrated solution for searching, analyzing, and visualizing data. Elasticsearch is widely used due to its ease of use, robust feature set, and strong community support.