1. As far as I know

Encyclopedia: AFAIK

• sidewards
• sideway
• sideways
• sidewinder
• sidewise
• siding
• sidle
• sidle up
• Sidney
• Sidney Caesar
• Sidney James Webb
• Sidney Poitier
• Sidney Webb
• Sidon
• Sidonie-Gabrielle Claudine Colette
• Sidonie-Gabrielle Colette
• SIDS
• siege
• siege of Orleans
• siege of Syracuse
• siege of Vicksburg
• siege of Yorktown
• Siege Perilous
• Siegfried
• Siegfried line