OLAP stands for “On-Line Analytical Processing”. We can summarize the OLAP definition in just five key words: Fast Analysis of Shared Multidimensional Information — or, FASMI for short. 

FAST means that the system is targeted to deliver most responses to users within about five seconds, with the simplest analyses taking no more than one second. 

ANALYSIS means that the system can cope with any business logic and statistical analysis that is relevant for the application and the user, and keep it easy enough for the target user. This could include specific features like time series analysis, cost allocations, currency translation, goal seeking, ad hoc multidimensional structural changes, non-procedural modeling, exception alerting, data mining and other application dependent features. These capabilities differ widely between products, depending on their target markets. 

SHARED means that the system implements all the security requirements for confidentiality (possibly down to cell level) and, if multiple write access is needed, concurrent update locking at an appropriate level. 

MULTIDIMENSIONAL is our key requirement. If we had to pick a one-word definition of OLAP, this is it. The system must provide a multidimensional conceptual view of the data, including full support for hierarchies and multiple hierarchies, as this is certainly the most logical way to analyze businesses and organizations. 

INFORMATION is all of the data and derived information needed, wherever it is and however much is relevant for the application.