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

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

His coauthor, Aswin Suresh, a graduate student in physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences, played a key role in the analysis.

From Science Daily • Oct. 9, 2025

The code, developed by study coauthor Kyungjae Im of Caltech, suggests that over a hypothetical 1,400-year period, there would be no repeatable patterns.

From Los Angeles Times • Aug. 11, 2025

Later, Elizebeth was named as coauthor on one of them.

From "The Woman All Spies Fear" by Amy Butler Greenfield