From the national AOA website:

Alpha Omega Alpha, commonly referred to as AOA, can be thought of as the "Phi Beta Kappa for medical schools." As the only national honor medical society, its mission, developed over the past one hundred years, has been to recognize and enhance professionalism, academic excellence, service, and leadership within the profession.

Election to Alpha Omega Alpha is an honor signifying a lasting commitment to scholarship, leadership, professionalism, and service. A lifelong honor, membership in the society confers recognition for a physician's dedication to the profession and art of healing.

For more information about AOA, please visit the national AOA website.