Big data has become a concern of science, industry, business, and academics, thus it is no more a buzzword but an emerging technology as viewed by researchers from different perspectives. Thus, different perspectives produced different definitions, of which none of them fully described big data. This research analysed some profound definitions based on discovered facts about big data. The facts are its characteristics, its technology, mode of transfer, its analysis, its infrastructure and security. Thus, a new definition was proposed which captures the basic facts about big data. Big data has its characteristics as foundations, and the rest facts as the pillars. These facts reflect in-depth meaning and understanding of big data to science, industry, business and academics.