A
Macintosh term for a
text object which carries with it various kinds of
formatting, such as font, style, and size information. If a region of styled text is copied and pasted from one application into another which recognizes styled text (such as a
word processor), the formatting is preserved. If it is pasted into an application which does not recognize the styling (such as a
terminal emulator or plain
text editor), it is automatically converted to
plain text.
(This may not sound like much of a radical idea. Keep in mind, though, that when the Macintosh introduced styled text, it was indeed a radical idea to be able to move formatted text -- or pretty much anything else -- from one desktop application to another without damage or heavy hand-hackery.)