Big data are data that are high volume, high velocity, and/or high variety; require new technologies and techniques to capture, store, and analyze; and are used to enhance decision making, provide insight and discovery, and support and optimize processes.
Source: Mills, S., S. Lucas, L. Irakliotis, M. Ruppa, T. Carlson and B. Perlowitz (2012). Demystifying Big Data: A Practical Guide to Transforming the Business of Government. Washington: TechAmerica Foundation.
Online: http://breakinggov.com/documents/demystifying-big-data-a-practical-guide-to-transforming-the-bus/
High volume—the amount or quantity of data
High velocity—the rate at which data is created
High variety—the different types of data In short, “big data” means there is more of it, it comes more quickly, and comes in more form
Source: Russom, P. (2011). Big Data Analytics, TDWI Best Practices Report. Seattle: The Data Warehousing Institute, Fourth Quarter.
Online: http://tdwi.org/research/2011/09/best-practices-report-q4-big-data-analytics.aspx