- (international standards, aviation) IATA airport code for General Juan N. Álvarez International Airport, which serves Acapulco, Guerrero, Mexico.
ACA (plural ACAs)
- (military) Initialism of airspace control authority.
- (military) Initialism of airspace coordination area.
- (accounting) Initialism of associate chartered accountant.
- (anatomy) Initialism of anterior cerebral artery.
- (immunology) Initialism of anti-cardiolipin antibody.
- (immunology) Initialism of anti-centromere antibody.
- (immunology) Initialism of antigen-capture assay.
- (US, politics) Initialism of Affordable Care Act (“H.R. 3590”)., from the U.S. national law "Affordable Care Act" (Patient Protection and Affordable Care Act)
- Initialism of Adult Children of Alcoholics.