Dot Matrix Printer,

Dot-Matrix Printer, in computer science, any printer that produces characters made up of dots using a wire-pin print head.

The quality of output from a dot-matrix printer depends largely on the number of dots in the matrix, which might be low enough to show individual dots or might be high enough to approach the look of fully formed characters. Dot-matrix printers are often categorized by the number of pins in the print head—typically 9, 18, or 24.