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

• chyliferous
• catholicity
• catholicization
• catholicize
• catholicized
• catholicizes
• catholicizing
• Catholic King
• catholicly
• Catholicoi
• catholicon
• catholicons
• Catholicos
• Catholicoses
• cathood
• cathoods
• cathouse
• cathouses
• Catilinarian
• Catiline
• cation
• cationic
• cations
• catkin
• catkins