Elasticsearch is licensed under the Elastic License 2.0, which is also a permissive open-source license. However, the Elastic License 2.0 has some restrictions on how Elasticsearch can be used and distributed. For example, you cannot use the Elastic License 2.0 to provide Elasticsearch as a service to others.
Community
OpenSearch is supported by a large and active community, including Amazon Web Services (AWS). Elasticsearch is also supported by a large community, but it is primarily supported by Elastic.
Features
OpenSearch and Elasticsearch have the same core features, including:
Search
Analytics
Aggregation
Visualization
Machine learning
However, OpenSearch is still under development, and it does not yet have all of the features of Elasticsearch. For example, OpenSearch does not yet support some of Elasticsearch’s advanced features such as cross-cluster replication and searchable snapshots.