Definition: Footnotes are additional pieces of information or commentary provided at the bottom of a page to clarify, expand on, or provide sources for points made in the main text. They are often marked with superscript numbers (¹,²,³) in the main body of the text. 

In rhetorical analysis, footnotes serve several purposes:

1. Providing Context: They offer historical, cultural, or technical background that enhances the reader’s understanding.

2. Adding Credibility: They cite sources or offer supporting evidence that strengthens an argument.

3. Maintaining Tone: Writers can keep the main text engaging while adding more scholarly, technical information in the footnotes.

4. Injecting Commentary: Some writers, like David Foster Wallace, use footnotes to add personal opinions, humor, or meta-commentary without disrupting the main narrative.