Big data refers to large, complex data sets that are rapidly generated and transmitted from a wide variety of sources. It encompasses the volume of information, the velocity or speed at which it is created, and the variety of data types frequently stored in big data systems. The definition of big data is data that contains greater variety, arriving in increasing volumes and with more velocity, also known as the three Vs. Big data can be categorized as structured, semi-structured, or unstructured.

The importance of big data lies in how it is used. By taking data from any source and analyzing it, businesses can find answers that streamline resource management, improve operational efficiencies, optimize product development, drive new revenue and growth opportunities, and enable smart decision making. Big data sets can be mined to deduce patterns about their original sources, creating insights for improving business efficiency or predicting future business outcomes.

Some notable areas where big data provides benefits include cost optimization, customer retention, decision making, and process automation. Big data technologies can be used for creating a staging area or landing zone for new data before identifying what data should be moved to the data warehouse.

In summary, big data is a term that describes large, hard-to-manage volumes of data – both structured and unstructured – that inundate businesses on a day-to-day basis. It is characterized by the three Vs: volume, velocity, and variety. The importance of big data lies in how it is used to gain insights and make informed decisions.