OLAP
In plain terms
Systems optimized for complex analytical queries.
Going deeper
Online Analytical Processing handles aggregations and multidimensional analysis over large datasets, unlike transaction-focused OLTP. It serves reporting and BI.
Under the hood
Read-heavy, denormalized, columnar; contrasts with OLTP's many small write transactions.
Examples
BI dashboards, cubes, data warehouses, trend analysis, reporting.
Think of it like...
Like a strategist studying big-picture trends rather than a cashier ringing up sales.