Your web application stores data in a Couchbase cluster using buckets. Buckets are isolated, virtual containers which logically group records within a cluster; they are the functional equivalent to a database. Buckets can be accessed by multiple client applications across a cluster. They provide a secure mechanism for organizing, managing and analyzing data storage. As an application developer you will most likely create buckets for your development and production environment.
For more information about data buckets in Couchbase Server, and how to create them, see Using Data Buckets and Couchbase Server 2.0 Manual, Data Buckets