Rolf Tesmer digs into the concept of BI:
Hunting the web for the general definition pulls up many one liners – and yes I guess everyone who is anyone will have a way to define it, and that definition is (or should) be based on their own experiences with building, deploying or supporting BI solutions.
If you are looking for a nice short collection of some of those definitions – and a further explanation of why you need BI – then this is a great post (http://www.jamesserra.com/archive/2013/03/why-you-need-business-intelligence/)
Rolf unpacks the definition and gives us some insight into the nature of Business Intelligence.