Enter key

On computer keyboards, the enter key and return key are two closely related keys with overlapping and distinct functions dependent on operating system and application. The return key has its origins in two typewriter functions: carriage return, which would reset the carriage to the beginning of the line of text, and line feed, which would advance the paper one line downward. These were often combined into a single return key, a convention that continues in modern computer word processing to insert a paragraph break (¶). The enter key is a computer innovation, which in most cases causes a command line, window form, or dialog box to operate its default function. This is typically to finish an "entry" and begin the desired process, and is usually an alternative to clicking an OK button. Additionally, it can act as the equal to button in calculator programs. On modern computers both keys generally have all the functions of the other, allowing for either key to be used, or even for them to be combined into a single key, as is the case with most laptops. Microsoft Windows makes no distinction between them whatsoever, and usually both keys are labelled as enter on Windows keyboards with the United States layout. Other operating systems, such as Apple's Darwin-based OSs, generally treat them equivalently while still maintaining the technical and descriptive distinction, allowing applications to treat the two keys differently if necessary. The enter key is typically located to the right of the and keys on the lower right of the numeric keypad, while the return key is situated on the right edge of the main alphanumeric portion of the keyboard. On ISO and JIS keyboards, return is a stepped double-height key spanning the second and third rows, below and above the right-hand . On ANSI keyboards it is wider but located on the third row only, as the backslash key is located between it and . Some variants of the ANSI keyboard layout create a double-height return key by subsuming the backslash key into it.