OLAP is short for Online Analytical Processing, a category of software tools that provide analysis of data stored in a database. OLAP tools enable users to analyse different dimensions of multi-dimensional data. For example, OLAP provides time series and trend analysis views.
The chief component of OLAP is the OLAP server. The OLAP server resides between a client and a database management system (DBMS). The OLAP server understands how data is organised in the database and has special functions for analysing the data. There are OLAP servers available for nearly all the major database systems.