thumb index


: a series of usually labeled notches cut in the fore edge of a book (such as a dictionary) to facilitate reference

Examples of thumb index in a Sentence

a dictionary that has a thumb index

Word History

First Known Use

1903, in the meaning defined above

Time Traveler
The first known use of thumb index was in 1903

Dictionary Entries Near thumb index

Cite this Entry

“Thumb index.” Dictionary, Merriam-Webster, Accessed 20 May. 2024.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!