Line Printer, in computer science, any printer that prints one line at a time, as opposed to one character at a time (as with a standard dot-matrix printer) or one page at a time (as with a laser printer).
Line printers typically produce the 11-by-17-inch “computer” printouts familiar to many. They are high-speed devices and are often used with mainframes, minicomputers, or networked machines rather than with single-user systems. Types of line printers include chain printers and band printers. The abbreviation LPT originally stood for “line printer”; on MS-DOS microcomputers, the same abbreviation is used for the computer's parallel output port(s).