What is the ElasticSearch equivalent to an SQL table?

In ElasticSearch, the concept which closely resembles an SQL table is called an index.

Compared to an SQL table, the index does not neccessarily need to have a predefined structure - the ElasticSearch index is more similar to a MongoDB collection.

However, an elasticsearch index has many features similar to SQL tables such as indices (which you typically don’t need to create explicity - ElasticSearch takes care of that for you).

Typically, indices contain lots of similar documents that have (mostly) the same properties.