What is Big Data?
In information technology, big data is a collection of data sets so large and complex that it becomes difficult to process using on-hand database management tools or traditional data processing applications. The challenges include capture, curation, storage, search, sharing, transfer, analysis, and visualization.
Big data is an umbrella term for data sets that are both structured (i.e. information in DBpedia or Wikidata is structured just like a large database) and unstructured (all the textual emails we daily exchange is unstructured).