General terms:
* Footnote: This is the most common term for a brief explanation or reference at the bottom of a page.
* Endnote: Similar to a footnote, but usually placed at the end of a document or chapter instead of at the bottom of each page.
* Explanation: This is a general term that can be used for any kind of text that clarifies something.
* Note: A general term that can be used for any kind of additional information.
* Appendix: A section at the end of a document that provides supplementary information.
More specific terms:
* Copyright notice: This is often found at the bottom of a page and states the copyright holder and year of publication.
* Website footer: This refers to the section at the bottom of a webpage that often includes links to other pages, copyright information, and contact details.
* References: This is a section at the bottom of a document that lists all the sources cited in the text.
* Glossary: A list of terms and their definitions, often found at the end of a document.
The specific term used will depend on the purpose and content of the explanation.