Rich Text
Text which contains formatting, such as bold, italics, and underlining, as well as different fonts, font sizes, and colors, as opposed to plain text which is unadorned text.
Rich text documents also include page formatting such as custom page margins, line spacing, and tab widths.
Most word processors, such as Microsoft Word, use their own rich text document type such as “.doc”, but a generic rich text format (“.rtf”) can be interchanged among most word processors.