The Theosophical Glossary (1892) by Helena Petrovna Blavatsky is a comprehensive reference work designed to define and explain key terminology used in 19th-century Theosophical literature, including Isis Unveiled, The Secret Doctrine, and The Key to Theosophy. As the final project Blavatsky was working on before her death, it serves as an essential guide to the specialized jargon of occultism, esotericism, metaphysics, and mythology. The 1892 publication was largely posthumous, with Blavatsky having only reviewed the first 32 pages in proof, but it remains a foundational text for understanding the terminology of the Theosophical movement.