Cyclopedias, also known as encyclopedias, are a compilation or collection of information. They provide an array of subjects and information on those subjects. Synonyms for cyclopedias include reference books, manuals, dictionaries, handbooks, compendiums, and atlases. Reference books are sources of factual information used for study or research. Manuals are books of instructions or guidelines. Dictionaries are reference books providing definitions of words or terms. Handbooks are comprehensive guides to a particular subject. Compendiums are collections of concise but detailed information. Atlases are books of maps and geographical information. In a nutshell, the use of any of these synonyms can act as an alternative when seeking specific information.