ff or ff.

1. Fecerunt (Latin), (they) did it or made it
2. Folios (printing)
3. Following pages, lines, etc
4. Fortissimo (music)

FF

1. Form feed (computing)
2. French franc or francs

• extollers
• extolling
• extolment
• extolments
• extols
• extorsive
• extorsively
• extort
• extorted
• extorter
• extorters
• extorting
• extortion
• extortionary
• extortionate
• extortionately
• extortioner
• extortioners
• extortionist
• extortionists
• extortions
• extortive
• extorts
• extra
• extra-