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

However, this research takes a more detailed approach by examining how specific fat storage patterns relate to neurological risk, said study coauthor Kai Liu, M.D.,

From Science Daily • Jan. 28, 2026

"If we don't understand the underlying tectonic processes, it's hard to predict the seismic hazard," said coauthor Amanda Thomas, professor of earth and planetary sciences at UC Davis.

From Science Daily • Jan. 17, 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

I have already written one cookbook as a coauthor called Mexican Food: The Ultimate Cookbook by Cidermillpress.

From Salon • Jan. 4, 2025

D’Alembert is best known for his collaboration on the famed Encyclopédie of human knowledge—a 20-year effort with coauthor Denis Diderot.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife