the process use of software techniques to identify valid, non-trivial, previously unknown, interesting relationships/global patterns that exist in large quantities of data.
knowledge discovery form data. extraction of interesting (non-trivial, implicit, previously unknown and potentially useful) patterns or knowledge from huge amounts of data.
the set of methodologies used in analyzing data from various dimensions and perspectives, finding previously unknown hidden patterns, classifying and grouping the data and summarizing the identified relationships.