subindex

/ˈsʌbˌɪndɛks/
noun
  1. A secondary or lower-level index, especially in a book, database, or list.
    • You can search the database by main category or use a subindex for more specific topics.
    • The report's subindex breaks down the data by region and year.
    • The subindex at the back of the book lists all the authors mentioned in each chapter.
Synonyms
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