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

• soil pipes
• soils
• soil science
• soilure
• soilures
• soily
• soirée
• soirées
• soixante-neuf
• soja
• sojas
• sojourn
• sojourned
• sojourner
• sojourners
• sojourning
• sojournings
• sojournment
• sojournments
• sojourns
• Soka Gakkai
• sokah
• sokaiya
• soke
• sokeman