Encyclopedia/ɪnˌsaɪkləˈpiːdiə/ Definition 1 of 2Pro Tip 1/3Extensive Coverage Encyclopedias cover wide topics, ideal for starting research or general knowledge. She read the entire encyclopedia set to broaden her knowledge. Pro Tip 2/3Subject Depth Some encyclopedias focus deeply on a single subject, offering detailed information. The medical encyclopedia had comprehensive details on diseases. Pro Tip 3/3Authority They are seen as credible sources, often edited by experts. His argument was supported by citations from a renowned encyclopedia.