Update: Amazon ElasticSearch Service has been rebranded as Amazon OpenSearch Service.
OpenSearch is a family of software consisting of a search engine (also named OpenSearch), and OpenSearch Dashboards, a data visualization dashboard for that search engine.
Amazon OpenSearch Service is a managed service that makes it easy to deploy, operate, and scale OpenSearch, a popular open-source search and analytics engine. OpenSearch Service also offers security options, high availability, data durability, and direct access to the OpenSearch API.
The software started in 2021 as a fork of Elasticsearch and Kibana, with development led by Amazon Web Services.