# ISBN

/ˌaɪˌɛsˌbiˈɛn/ (US) · CEFR B2 · Noun

Source: https://englishreference.com/word/isbn
Updated: 2026-05-10

## Definition

Stands for International Standard Book Number — a unique identifier assigned to each edition of a book, used by publishers, booksellers, and libraries to catalogue and order titles.

For teachers: Abbreviation for International Standard Book Number. A 13-digit (formerly 10-digit) numeric commercial book identifier assigned to each separately-issued edition of a book or book-like product. Administered internationally by the International ISBN Agency; encoded in the EAN-13 barcode on the back cover. Distinct from the ISSN, which identifies serial publications.

## Examples

- You can find the book easily if you have its ISBN.
- The librarian asked for the ISBN to ensure she ordered the correct edition of the textbook.
- While the title and author remain the same, the hardcover and paperback versions of the novel are assigned a different ISBN to distinguish them in the global supply chain.

## Pitfalls

- Not "the ISBN number" but "the ISBN" — While common in speech, 'ISBN number' is technically redundant because the 'N' already stands for 'Number'.

## Usage notes

- Often used with the definite article ('the ISBN') or as a modifier ('ISBN number').

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.