A database is a: large collection of data organized especially for rapid search and retrieval (as by a computer).
Basically, a database is an electronically organized catalog, index, and container for published information such as journal, newspaper, and magazine articles, as well as ebooks, streaming video and audio files.
A database is either general or subject/discipline specific and is searchable by keyword, subject, author, or title.
Library databases vary in content and design, many provide provide scholarly and peer-reviewed sources that are appropriate to use for academic research and writing.