Elastic search is an analytics and search engine which is open source and distributed. It is developed in Java language and built on Apache Lucene. It allows you to store, search, and analyze large amounts of data faster and even in milliseconds. It is able to receive such a fast response because rather than searching the data directly it searches for its index. It uses a structure based on documents rather than database schemas. You can just imagine Elastic Search of a server receiving a json request aand responding back with a json response.

https://erpsolutions.oodles.io/developer-blogs/Basics-of-ElasticSea...