Summaries, usually of journal articles. Searchable collections of references with abstracts are known as bibliographic databases. The term 'Abstracts' is sometimes used to refer to printed indexes of publications which include an abstract for each item listed.
These are tools to help you find periodical (journal, magazine, or newspaper) articles and other sources of information. They also provide brief summaries of articles. Most abstracts have a specific focus, such as Sociological Abstracts or Biological Abstracts. Abstracts can be in a print format, an electronic format, or both. Now, many abstracts are in electronic format and are often referred to as databases. The word abstract also refers to a summary of an article or book.