B84 may refer to :

• B84 (New York City bus) in Brooklyn
• Bundesstraße 84, a German road
• Faakersee Straße, an Austrian road
• Sicilian Defence, Scheveningen Variation, Encyclopaedia of Chess Openings code

• Eureka (search engine)
• Eureka seveN
• Eureka seven
• Eureka Seven in other media
• Eureka seven (Media)
• Eureka Seven (Media)
• Eureka Seven New Wave
• Eureka Seven: New Wave
• Eureka Seven vol 1: New Wave
• Eureka Seven vol. 1 New Wave
• Eureka Seven vol 1 New Wave
• Eureka Seven Vol. 1: The New Wave
• Eureka Seven Vol. 2: The New Vision
• Eureka, Spencer County, Indiana
• Eureka Springs High School
• Eureka Springs High School (Eureka Springs, Arkansas)
• Eureka Stockade (1949 film)
• Eureka Street (magazine)
• Eureka Street (tv)
• Eureka Street (TV series)
• Eureka (television)
• Eureka Television Group
• Eureka Transit Service
• Eureka! (TV series)
• Eureka (University of Cambridge magazine)