1. A form of daylight-saving time, one hour ahead of UTC, used in the United Kingdom, Ireland and mainland Portugal in summer
   - BST, Irish Standard Time, Western European Summer Time

Encyclopedia: British Summer Time

• sidereal time
• sidereal year
• siderite
• Sideritis
• sideroblast
• sideroblastic anaemia
• sideroblastic anemia
• siderochrestic anaemia
• siderochrestic anemia
• siderocyte
• siderolite
• sideropenia
• siderophilin
• siderosis
• siderostat
• sidesaddle
• sideshow
• sideslip
• sidesman
• sidesplitter
• sidesplitting
• sidesplittingly
• sidestep
• sidestroke
• sideswipe