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

• copper-nickel
• copper-nickels
• copper nose
• copper noses
• copperplate
• copperplates
• copper pyrites
• coppers
• copperskin
• copperskins
• coppersmith
• coppersmiths
• copper sulphate
• copper sulphates
• copperwork
• copperworks
• copperworm
• copperworms
• coppery
• coppice
• coppiced
• coppices
• coppicing
• coppicings
• coppies