ISA

The acronym I.S.A. refers to several articles on Wikipedia:

Aeronautics and Space Exploration

• International Standard Atmosphere: International Standard Atmosphere, Earth Atmospheric Model Used for Air Navigation
• Iranian Space Agency, Iranian Space Agency
• Israeli Space Agency, Israel Space Agency
• Italian Space Agency, Italian Space Agency

Computing

• Instruction Set Architecture, instruction set architecture
• Industry Standard Architecture, industry standard architecture, expansion slot for motherboards
• Microsoft Internet Security and Acceleration Server, Microsoft Internet Speed and Security Server

Security

• Advice_Independent_de_Security, Independent Security Advice. ISA (Independent Safety Asessment)

• Electric Interconnection S.A., a multinational business group of electricity originating in Colombia.
• Infectious anemia of salmon, viral disease of the Atlantic salmon, which does not affect the human being.
• Instituto Superior de Arte en La Habana (Cuba)
• International Seabed Authority, International Seabed Authority
• International Sociological Association, International Sociology Association
• International Solar Alliance, International Solar Alliance
• International Strategic Alliance: International Strategic Alliance, fictional organization of the Killzone universe.
• International Surfing Association, International Association of Surfing
• International Symbol of Access, International Symbol of Accessibility, also known as an international symbol of the wheelchair.
• Instrumentation, Systems and Automation Society, International Society for Automation