If two or more people co-author a book, play, or report, they write it together. He's co-authored a book on Policy for Tourism Karen Matthews co-authored the study with Lewis Kullers
The co-authors of a book, play, or report are the people who have written it together. He is co-author, with Andrew Blowers, of `The International Politics of Nuclear Waste'
Any member of either house, with the agreement of the author of a bill, may add his or her name on that member's bill as coauthor, usually indicating support for the proposal
A legislator authorized by the primary author to join in the authorship of a bill or resolution A coauthor must be a member of the chamber in which the bill was filed