CouchDB is an open source NoSQL document-oriented database. Couch is an acronym for Cluster Of Unreliable Commodity Hardware. It is largely written in Erlang, a concurrent, functional programming language.
CouchDB was developed by Damien Katz, who formerly worked on Domino 6 of the IBM Notes/Domino platform, and was first released in 2005 under GNU GPL. In 2008, it became part of the Apache project and hence been offered under Apache License.