Dictionary.com
Thesaurus.com

ff

American  

abbreviation

  1. folios.

  2. (and the) following (pages, verses, etc.).

  3. Music. fortissimo.


ff British  

symbol

  1. folios

  2. following (pages, lines, etc)

  3. music fortissimo: an instruction to play very loudly

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012