1S

1S or 1s may refer to:

• 1s electron, in an atomic orbital
• Sabre (computer system)'s IATA code
• 1S, a series of Toyota S engines
• SSH 1S (WA); see Washington State Route 502, Washington State Route 503
• One shilling (British coin)

See also

• Shilling
• Second
• Ones (disambiguation)
• S1 (disambiguation)