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

• side glance
• side glances
• side issue
• sidekick
• sidekicks
• sidelight
• sidelights
• sideline
• sidelined
• sidelines
• sideling
• sidelining
• sidelock
• sidelocks
• sidelong
• sideman
• side meat
• side meats
• sidemen
• sidenote
• sidenotes
• side-on
• sidepath
• sidepaths
• side plate