Please see: http://wikisuite.org/Elasticsearch

All still relevant info below should be migrated.

Elasticsearch is a distributed, RESTful, free/open source search server based on Apache Lucene."

It is an optional component of Tiki Suite, if you need faster and / or better search results. You can add at any time. It is interoperable with Tiki, starting in Tiki12. It permits some Natural Language Processing features.

See also other apps of "The Elasticsearch ELK Stack":

Use case 

How to install & configure Elasticsearch, Tiki and ClearOS 

Related links