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

"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

Ferhan Sakal, head of excavation and site management at Qatar Museums and a coauthor of the study, noted that crucial information about past seagrass environments is preserved in the region's rock record.

From Science Daily • Dec. 12, 2025

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

“It came as a surprise that you could get such a long rupture,” said Jean-Philippe Avouac, a coauthor of the study and a professor of geology and mechanical and civil engineering at Caltech.

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