Select the most appropriate one-word substitution for the given group of words. 

Adding notes to give explanation or comment about something.

Annotate

The most appropriate one-word substitution for adding notes to give explanation or comment about something is annotate.

• Anecdote is a short, amusing or interesting story about a real person or event.
• Anarchy is a state of disorder or lawlessness.
• Index is a list of items in a book or document, usually arranged alphabetically or by subject.

The word annotate is derived from the Latin word annotare, meaning "to write notes". It is the act of adding notes to a text or document to explain or comment on it. Annotations can be used to provide additional information, clarify a point, or offer a personal interpretation.