“Font” used to refer to a single set of metal movable type of the same style in the same size. A “single set” referred not just to the twenty-six letters of the alphabet, in the case of European languages, but each of those letters in both upper- and lower-case, Roman and Italic forms, as well as numbers and symbols (including punctuation marks such as periods and commas, quotation marks, and other forms of notation).

Today, when composition done on computers is increasingly common and font size can be changed freely, “font” has gradually lost the sense of being of a uniform size, and has become effectively synonymous with the Japanese shotai, which refers to characters of a uniform style. When the word “font” is used in the context of desktop publishing (DTP), it usually refers to the data of a given font style. In this sense the term “digital font” is sometimes used to distinguish it from metallic fonts. Digital fonts are essential for displaying characters on computer screens and producing characters on printers.

Digital fonts are divided into two basic types: bitmap fonts and outline fonts. Bitmap fonts store character shapes as a collection of small dots; as a result, roughness is produced as font sizes increase. This sort of font is employed when fine detail is not necessary, as with the characters printed on a receipt. Outline fonts store character shapes as numerical data, allowing characters to be produced in any size without any deterioration in quality. As a result, they are used for producing printed documents. (Such documents also depend on the quality of the output device.) Fonts come preloaded on computers, but in certain situations – such as when a new font is desired for DTP, or when slightly different fonts are needed for a design – additional fonts must be purchased from font developers.