A font is a collection of graphic characters sharing type family, style, and weight. You can use a font for an entire data set or file, for an entire page, or for selected lines or fields of data on a page. Page printers can print fonts with various point sizes, styles, weights, and widths on a single line or on various lines on a page. Multiple fonts can be printed on a page. Before each page is printed, the fonts required for the page are sent to the printer (downloaded) if the printer does not already have them in its storage. The printer storage required for a font depends on the point size (for raster fonts), number of characters in the font, and whether the font is double-byte or single-byte.
To understand fonts, you should be familiar with basic font concepts, including font terminology, how font characters are represented, the characteristics of font spacing, and point and pitch sizes.