AHA is a three-letter abbreviation with multiple meanings, as described below: Hor-Aha an Egyptian Pharaoh of the 31st century BC The Association of Hispanic Arts The American Historical Association a-ha, a Norwegian pop music band American Heart Association American Hebrew Academy American Hockey Association American Homebrewers Association American Humanist Association American Humane Association Alpha Hydroxy Acid aha! is an exclamation used when one gets a sudden idea, or simply in a moment of discovery or clarity, often a moment of surprise.