An editorial, leader (UK), or leading article (UK) is an article in a newspaper or magazine that expresses the opinion of the editor, editorial board, or publisher.
http://en.wikipedia.org/wiki/Op-Ed

Publish Your Opinion Worldwide... Right Here, on OpEd.com! Sample Topics: Censorship Abortion War Medicine Civil Rights National Politics
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Op-Ed: Women in Combat. There's a disconnect between what U.S. policy says female soldiers can do and what they are actually doing; this needs to change so that they can get the ...
http://www.nytimes.com/pages/opinion/index.html

noun . a newspaper page devoted to signed articles by commentators, essayists, humorists, etc., of varying viewpoints: the Op-Ed of today's New York Times.
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An op-ed, abbreviated from opposite the editorial page (though often believed to be abbreviated from opinion-editorial), is a newspaper article that expresses the opinions of a ...
http://en.wikipedia.org/wiki/Op_ed