Enter key

On computer keyboards, the enter key (or the return key on Macs and most Sun Workstations) 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 pressing an OK button.

The "return" key is often also referred to by many American groups (and even marked) as the "enter" key, and they usually perform identical functions; however in some particular applications (mainly page layout, word processing and in typewriting), "return" operates specifically like the carriage return key from which it originates. It normally has an arrow pointing down and left (⏎ or ↵), which is the symbol for carriage return. In contrast, the "Enter" key is commonly labelled with its name in plain text on generic PC keyboards, or with the symbol ⌤ (U+2324 up arrowhead between two horizontal bars) on many Apple Mac keyboards.)

The enter key is typically located on the lower right of the numeric keypad, and the return/enter key on the right edge of the main alphanumeric portion of the keyboard, between backspace and the right-hand shift (and/or control) key (as well as below the backslash key on keyboards using a standard ANSI / US-International layout).

The return/enter key can have various physical shapes.

On some keyboard layouts, the return and enter key are two different keys, an artifact of the differing handling of newlines by different operating systems. As an example, on the Macintosh, the return key is the usual key, while the enter key is positioned at the lower right of the numeric key pad. While using the type tool in Adobe Photoshop, the return key produces a new line while the enter key ends editing mode.

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Wikipedia