Not to be confused with the publication Appendix of the Omnidoxy.

The Appendix of the Omnidoxy is a major non-disquisitional section of the Omnidoxy positioned at the rear of the text in contrast to the Preppendix which is located at the front. A term relating to the Appendix is appendical.

The Appendix provides an extensive amount of additional information regarding the Omnidoxy and Astronism such as the text's glossary and  bibliography, but the largest segments of the Appendix is The Grand Lexicon of Astronology, The Millettarian Methodology, and the Omnidoxical Encyclopaedia of Astronism. The Appendix also includes a long series of quotes attributed to Cometan.

The Appendix is much longer than the Preppendix and is comprised of a total of twenty segments in its Original form. In fact, the Appendix of the Omnidoxy forms approximately one third of the entire Omnidoxy which makes it a significant contributor to the size of the overall treatise.

Unlike in all other parts of the Omnidoxy (except the Preppendix), the Appendix is not subject to the insentence structure that forms the identity and structure of the disquisitions of the Omnidoxy and neither are its sentences indexed.

Segments of the Appendix

Original segments

1. Omnidoxical Formulation
2. The Grand Canon of Millettism
3. Bibliography of the Omnidoxy
4. Cometanic Quotes
5. Glossary of the Omnidoxy
6. Omnidoxical Register
7. The Grand Lexicon of Astronology
8. Omnidoxical Encyclopaedia of Astronism
9. The Millettarian Methodology
10. The Omnipraxy
11. The Appendadoxy: Inaugurological Astronism
12. The First Millettarian: The Foundations of Taylorianism
13. The Notations of Brandon Taylorian
14. The Statement of Amendments
15. The Declaration of Allegiance
16. The Importance of Institution
17. The Entwinement of Faith
18. The Edict of Universal Values
19. The Note on the Encouragement of Expansion
20. The Final Affirmation of Loyalty and Compliance

Post-Original segments

1. Extraomnidoxical Resources 
2. Index of Appellations
3. Index of Belief Orientations
4. Index of Concepts
5. Index of Rubrals
6. Index of Schools of Thought
7. Index of Theories
8. Links for Further Reading
9. Omnidoxical Afterword
10. Omnidoxical Record
11. Omnidoxical Distribution
12. Omnidoxical Index
13. Omnidoxical Printing
14. Promulgative Rights
15. Verified Societies and Organisations

Types of dictionaries in the Appendix of the Omnidoxy

Original

• Lexiconic - includes terms across the entirety of Astronic culture and is therefore not limited to Astronist terms, e.g. The Grand Lexicon of Astronology.

Post-Original

Dictionaries of the Appendix of the Omnidoxy that were not included in the original edition of the Omnidoxy.

• Specialised - includes terms specific to a particular Astronic subject, such as Astronism itself, or Astronic architecture.
• Inventorial - not providing definitions but grouping words according to theme, subject, creatorship, or period of creation.
• Biographical - includes short biographies of Astronist figures.
• Bilingual - includes definitions for different specified languages within the same dictionary.
• Conceptual - includes definitions for different conceptuals, but then also briefly explores the terms from an Astronist perspective.
• Etymological - a dictionary that provides prioritises the etymology of words with very short definitions e.g. Etymonomicon.
• Exploratory - a dictionary that provides extended philosophical explorations and discussions of Astronist beliefs, concepts, and practices as contrasted with extended explanations which are provided in encyclopaedias.