In medicine and health:
* N-acetylcysteine: A medication used to treat acetaminophen overdose and for other conditions.
* National Accreditation Council: A body that accredits healthcare institutions in some countries.
In other contexts:
* National Association of Counties: An organization that represents counties in the United States.
* National Association of Colleges and Employers: An organization that provides information about career development and job opportunities.
* National Association of Chain Drug Stores: An organization that represents chain drug stores in the United States.
* National Association of Conservation Districts: An organization that represents conservation districts in the United States.
It's important to consider the context of the acronym to understand its meaning. If you can provide more information about where you encountered "NAC," I might be able to give you a more specific answer.