This document provides an overview of big data, including its definition, characteristics, sources, tools, applications, risks and benefits. It defines big data as large volumes of diverse data that can be analyzed to reveal patterns and trends. The three key characteristics are volume, velocity and variety. Examples of big data sources include social media, sensors and user data. Tools used for big data include Hadoop, MongoDB and analytics programs. Big data has many applications and benefits but also risks regarding privacy and regulation. The future of big data is strong with the market expected to grow significantly in coming years.