Definition of Aab

AAB is a three-letter acronym that may refer to:

• Aalborg Boldspilklub, a Danish sports club
• ABN AMRO, the largest bank in the Netherlands
• Alice Bailey, new age writer often referred to by her initials as AAB
• Air Assault Badge, a United States Army military badge
• Akita Asahi Broadcasting, a television station in Akita Prefecture, Japan
• Anti-aircraft battery, a weapons system component for anti-aircraft warfare
• The Atlas of Australian Birds, two books and a database of the Royal Australasian Ornithologists Union
• IATA airport code for Arrabury Airport in Queensland
• ICAO airline designator for Abelag Aviation in Belgium
• Antigua and Barbuda
• Ancient Art of Boar, Andrew W.K.'s first solo project, started when he was 15 years old.

Aalborg Boldspilklub is a Danish professional sports club based in the city of Aalborg. The club is also known as Aalborg BK or AaB for short. Through time the club has had branches in cricket and tennis, but currently controls teams in football, ice hockey and handball. All teams are competing in the top-flight Danish league in their respective sport. The kit sponsor for the club is hummel, and the principal sponsor for the football and handball team is the regional bank Spar Nord.