From the new quarterly update of the Oxford English Dictionary:
big data n. Computing (also with capital initials) data of a very large size, typically to the extent that its manipulation and management present significant logistical challenges; (also) the branch of computing involving such data.
1980 C. Tilly Old New Social Hist. & New Old Social Hist. (CRSO Working Paper No. 218) 8 None of the big questions has actually yielded to the bludgeoning of the big-data people.
2003 R. Williams in F. Berman et al. Grid Computing xxxviii. 850 The recognition that big data is a gold mine and not just a collection of dusty tapes.
2012 Australian (Nexis) 9 Oct. 37 At the heart of Big Data are two open source technologies—the Hadoop open-source framework.., and the MapReduce programming model.