coauthor

American  

[koh-aw-ther, koh-aw-] / koʊˈɔ θər, ˈkoʊˌɔ- /

noun

1. one of two or more joint authors.

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verb (used with object)

1. to write in joint authorship.

coauthor British  

/ kəʊˈɔːθə /

noun

1. a person who shares the writing of a book, article, etc, with another

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verb

1. (tr) to be the joint author of (a book, article, etc)

Etymology

Origin of coauthor

First recorded in 1860–65; co- + author

Explanation

A coauthor is someone who works with another person to write something. If three people take turns writing chapters of a novel, each of them can call herself a coauthor. You can spell the noun coauthor with or without a hyphen — co-author is also correct. Whenever it takes more than one person to write a book, the book can be said to have coauthors. And if you collaborate with a friend on a hand-written magazine, you are one of its coauthors. The word comes from author, or writer, and the prefix co, which means "together" or "mutually."

Example Sentences

Fernando and his coauthor, Constantinos Charalambous, a research fellow at Imperial College London, tested the technique by analyzing the reentry of debris from China's Shenzhou-15 spacecraft.

From Science Daily • Jan. 24, 2026

Karen Manship, coauthor and Managing Director at the American Institutes for Research, noted that Montessori programs are already widespread in public education.

From Science Daily • Jan. 1, 2026

One of those senators, Russ Feingold—the coauthor of the McCain-Feingold campaign finance law—was particularly vulnerable, as he was up for reelection that year.

From Slate • Oct. 21, 2025

Andrews was a coauthor of the New York Declaration on Animal Consciousness, a declaration signed last April by a long list of animal consciousness, philosophy, neuroscience and cognitive science luminaries at New York University.

From Salon • May 13, 2025

He was the coauthor of the then latest edition of the modern bible of chess, Modern Chess Openings, which contained thousands of variations, positions, analyses, and recommendations.

From "Endgame" by Frank Brady