Clean Air Act, a number of pieces of legislation relating to the reduction of smog and atmospheric pollution

Continental Airlines Arena, an arena in East Rutherford, New Jersey

Colonial Athletic Association, an NCAA Division I college athletic conference whose members are located in East Coast states from Massachusetts to Georgia

Creative Artists Agency, American show business agency

The amino acid codon for glutamine

China Academy of Art, the highest university of art in China which founded in 1928

Computational Aeroacoustics, direct simulation of acoustic fields generated by flows and of the interaction of acoustic fields with flows

Canadian Avalanche Association, a non-profit organization that promotes avalanche awareness and safety

College Art Association, an organization that supports all practitioners and interpreters of visual art and culture, including artists and scholars, who join together to cultivate the ongoing understanding of art as a fundamental form of human expression. Representing its members' professional needs, CAA is committed to the highest professional and ethical standards of scholarship, creativity, connoisseurship, criticism, and teaching

Central African Airways, national carrier for Southern Rhodesia, then the Central African Federation

Confederation of African Athletics

Carinthian Astronomical Association (Astronomische Vereinigung Kärntens)

Canadian Automobile Association, non-profit federation of nine clubs across Canada, providing roadside assistance services

Cerebral amyloid angiopathy, a form of angiopathy in which the amyloid protein associated with Alzheimer's disease deposits in the walls of the blood vessels of the brain

Civil Aviation Authority, name for the national body governing civil aviation in a number of countries

Center for American Archeology, in Kampsville, Illinois, an independent non-profit 501(c)3 research and education institution

Center for Academic Advancement, a part of the Johns Hopkins University Center for Talented Youth

Cyprus Automobile Association non-profit organisation, providing roadside assistance services

Case Alumni Association, oldest independent alumni organization in the United States

CAA is the ICAO airline designator for Atlantic Southeast Airlines in the United States