A thumb index, also called a cut-in index[1] or an index notch,[2] is a round cut-out in the pages of dictionaries, encyclopedias, Bibles and other large religious books, and various sectioned, often alphabetic, reference works, used to locate entries starting at a particular letter or section. The individual notches are called thumb cuts and enable the reader to turn to any section they want.

A dictionary with thumb indexes (on the right).

Several ways to achieve this indexing effect were invented and patented in the 1970s by Arthur S. Friedman, a printing engineer in New York.[3] Charles Halbert Denison also patented the marginal thumb indexing system for bookkeeping,[4] with his business taken over by his wife Dimies T. Stocking Denison after his death in 1911.[5][6]

See also

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References

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  1. ^ "thumb index". Bookbinding and the Conservation of Books: A Dictionary of Descriptive Terminology. Foundation of the American Institute for Conservation. Retrieved 8 May 2012.
  2. ^ Popular Mechanics. Hearst Magazines. Sep 1956. p. 184.
  3. ^ "Google Patents". patents.google.com.
  4. ^ "CHARLES H DENISON DEAD". Evening Times-Republican. Marshalltown, Iowa. July 13, 1911. p. 2.
  5. ^ "CHARLES H DENISON DEAD". Evening Times-Republican. Marshalltown, Iowa. July 13, 1911. p. 2.
  6. ^ Samuelson, N. L.; McCarty, Milton; Maloney, Russell (1937-12-03). "Thumb-Indexing". The New Yorker. ISSN 0028-792X. Retrieved 2025-06-23.