What is ABN?

Original: It is Alabama Board of Nursing

Yes it can stand for Alabama Board of Nursing, however it depends on the context of the abbreviation.

ABN is the standard abbreviation for Abnormal however in different context it can mean other things.

Military: Airborne

Business: Assumed Business Name

Mind you that with acronyms there can be tons of meanings and it would be easier to answer if you provide the situation in which the Acronym/Abbreviation is used.