An ill-defined term for large collections of data of various sorts. Big data may be big because it includes a large number of records (e.g., all of the transactions on Amazon), because it includes a large number of variables (all of the characteristics or features that a bank knows about each customer), or both. Big data often suffers from the 4-Vs: Velocity, Variety, Volume, and Veracity. Big data accumulate very rapidly, they consist of many different kinds of data, at high volume, and the quality of the data often presents a challenge. Big data can also refer to very large collections of electronically stored information.