One who founds something, such as an organization, together with someone else(noun)
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Use "cofounder" in a sentence
"However this announcement is significant because, I think it is the first time an Arab tech company acquires an American IT company, Dial’s cofounder is Arabic i think. reply"
"At the end of his four minutes, the presenter told the audience that his "cofounder is the one in the back wearing the same sweet t-shirt.""
"The contribution from Moskovitz, who listed his occupation simply as "cofounder," highlights the bizarre position Facebook has put itself in by blocking speech on behalf of a political position backed by many of its users and at least one of its founders."