504 may refer to:

• 504, a year
• Avro 504, a World War 1 era biplane aircraft built by Avro
• Peugeot 504, a large family car
• Area code 504, telephone code in Louisiana, United States
• Section 504 of the Rehabilitation Act, which protects Americans with disabilities from discrimination by any entity that receives Federal funding
• 504 Gateway Timeout, a server error in web browsing etc. – see List of HTTP status codes § Server errors
• 504 King, a streetcar route in Toronto, Canada
• No. 504 Squadron RAF, of Britain's Royal Air Force
• List of highways numbered 504

Topics referred to by the same term

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