504 may refer to: * 504, a year * Avro 504, a World War 1 era biplane aircraft built by A. V. Roe and Company, * Peugeot 504, a car * Area code 504 * Section 504 of the Rehabilitation Act, which protects Americans with disabilities from discrimination by any entity that receives Federal funding. * HTTP status code 504 * 504 King, a streetcar route operated by the Toronto Transit Commission * No. 504 (County of Nottingham) Squadron, RAuxAF This disambiguation page lists articles associated with the same number. If an internal link led you here, you may wish to change the link to point directly to the intended article.