TV's Frink said:

At the risk of sounding more stupid than usual...what's a linefeed?

US-ASCII (and character-sets derived from it, including Latin-1 and UTF-8) has two character-codes that signify "move to the next line":

10: Line Feed, a.k.a., New Line

13: Carriage Return

http://www.asciitable.com/index/asciifull.gif

*n*x systems (e.g., GNU/Linux) use a single Line Feed to represent newlines. Classic pre-OSX Mac systems used a single Carriage Return to represent newlines. Microsoft systems (e.g., MS-DOS and Windows) use a Carriage Return followed by a Line Feed to represent newlines.

These terms come from the typewriter days of old...

Carriage Return -> return the carriage to the start position

Line Feed -> move to the next line on the paper