In computer text processing, a markup language is a system for annotating a document in a way that is syntactically distinguishable from the text, meaning when the document is processed for display, the markup language is not shown, and is only used to format the text. The idea and terminology evolved from the "marking up" of paper manuscripts (i.e., the revision instructions by editors), which is traditionally written with a red or blue pencil on authors' manuscripts. Such "markup" typically includes both content corrections (such as spelling, punctuation, or movement of content), and also typographic instructions, such as to make a heading larger or boldface.