Copy editors perform quality control for publications. Within the industry, they are known as "the last line of defense." Although copy editing is concerned with style, there is no universal form for the term itself. In magazine and book publishing, it is often written as one word. The newspaper industry writes the expression as two words or hyphenates it. The terms "copy editor" has a similar division between one word or two. The job is called "sub-editing" in the United Kingdom.