Encyclopedical is a word that describes something that is comprehensive and covers a broad range of topics. Synonyms for this word include encyclopedic, inclusive, all-encompassing, extensive, thorough, and comprehensive. These words suggest a deep level of research and attention to detail. When describing a book, article, or person's knowledge, using one of these synonyms can convey that the information is vast and trustworthy. The usage of encyclopedical terminology can lend an air of authority and credibility to a piece of writing or to a person's level of expertise, leading to a better understanding of a particular subject.