The term big is relative and can often take on different meanings, both in terms of magnitude and applications for different situations. A simple, although naïve, definition of big data is a large collection of information, whether it is data stored in your personal laptop or a large corporate server that is non-trivial to analyze using existing or traditional tools.

Today, the industry generally treats data in the order of terabytes or petabytes and beyond as big data. In this chapter, we will discuss what led to the emergence of the big data paradigm and its broad characteristics. Later on, we will delve into the distinct areas in detail.