Background sources such as, but not limited to, dictionaries and encyclopedias provide context for your topic or even help you choose one. Researchers use them when they need:
Encyclopedia, dictionary and biographical entries from hundreds of sources for most subject areas. It includes images, diagrams, maps and photos, and audio pronunciation files and sound clips. Coverage 2000 – present.
Encyclopedia and dictionary entries for most subject areas. Dates covered: latest edition of each title.