B9

B9, B IX or B-9 may refer to:

• B9 (Croatia), a road part of the Istrian Y highway complex
• B9 (New York City bus) serving Brooklyn
• Bavarian B IX, an 1874 German steam locomotive model
• Bavarian B IX (Ostbahn), an 1869 German steam locomotive model
• Bensen B-9, a 1958 American small helicopter
• Boeing B-9, a 1931 all-metal monoplane bomber aircraft designed for the United States Army Air Corps
• HMS B9, a British Royal Navy B-class submarine
• Iceberg B-9, a 1987 iceberg calved away from Antarctica
• Model B-9, otherwise known simply as "Robot" on the TV series Lost in Space
• Prodelphinidin B9, a plant phenolic compound
• Vitamin B₉, another name for folic acid

and also :

• the abbreviation used for the record label Bridge Nine
• the former model name for the Subaru Tribeca
• the IATA code for Iran Airtour
• the former IATA code for Air Bangladesh
• a subclass of B-class stars
• Boeing Y1B-9, a bomber of the United States Army Air Corps
• an international standard paper size (44×62 mm), defined in ISO 216