Also called the "Return key," it is the keyboard key that is pressed to signal the computer to input the line of data or the command that has just been typed. It Was the Return Key The Enter key was originally the "Return key" on a typewriter, which caused the carriage to return to the beginning of the next line on the paper. In a word processing or text editing application, pressing Enter ends a paragraph. A character code for return/end-of-line, which is different in Windows than it is in the Mac, Linux or Unix, is inserted into the text at that point. See CR/LF.