Form feed
The FF control character (0x0C) that tells a printer to eject the current page and move to the top of the next.
Form feed is the ASCII character number 12, 0x0C, Ctrl-L, meaning roughly "drop this page, start the next one." On line printers running continuous form paper it rolled the paper up to the next form boundary; on sheet printers it ejects the page. The character lived on in text files and print streams as a plain page break, and for years most printers carried a physical Form Feed button that did the same thing by hand.
It comes from the world of line printers and teletypes, where output was one unbroken ribbon of paper and you needed a way to say where one page ended and the next began.