Business intelligence is a method of storing and presenting key enterprise data so that anyone in your company can quickly and easily ask questions of accurate and timely data. Effective BI allows end users to use data to understand why your business go the particular results that it did, to decide on courses of action based on past data, and to accurately forecast future results.
A single structure that usually, but not always, consists of one or more cubes.
A defined subset of a data warehouse, often a single cube from a group. It represents one business unit.
A storage structure used by classic data warehousing products in place of many. Cube usually present data that is aggregated, rather than each individual item. Cubes present a summarized, aggregated view of enterprise data, as opposed to normalized table sources that present detailed data.
Decision Support System
The term’s broad definition can mean anything from a read-only copy of an online transaction processing (OLTP) database to a group of OLAP cubes or even a mixture of both.
ETL is abbreviation of Extraction, Transform, and Load.
OLAP is abbreviation of online analytical processing.
OLTP is abbreviation of online transactional processing.
Reference : Pinal Dave (http://blog.SQLAuthority.com) , SQL SERVER – Data Warehousing Interview Questions and Answers Complete List Download