| Acronym | Definition |
|---|
| ISA | Industry Standard Architecture (PC slot type) |
| ISA | Internet Security and Acceleration (Microsoft firewall and cache server) |
| ISA | Is A (entity hierarchy in extended entity-relationship data model) |
| ISA | Instruction Set Architecture |
| ISA | Individual Savings Account (UK) |
| ISA | Internal Security Act |
| ISA | International Studies Association |
| ISA | Independent Safeguarding Authority (UK) |
| ISA | International Student Association |
| ISA | Instrumentation, Systems, and Automation Society (now International Society of Automation) |
| ISA | Isaiah |
| ISA | International Society of Automation (est. 1945) |
| ISA | International Sociological Association |
| ISA | International Society of Arboriculture |
| ISA | International Standard on Auditing |
| ISA | Indian Student Association |
| ISA | India Semiconductor Association (Bangalore, India) |
| ISA | International Students Association |
| ISA | Instrument Society of America (now International Society for Measurement and Control) |
| ISA | International Searching Authority |
| ISA | Instituto Socioambiental (Portuguese: Socio-Environmental Institute; Brazil) |
| ISA | Intelligent Speed Adaptation |
| ISA | International Society of Appraisers |
| ISA | International Seabed Authority |
| ISA | Inshaallah |
| ISA | International Schools Association |
| ISA | Insurance Services of America (Christian insurance organization) |
| ISA | IBM Support Assistant |
| ISA | Irish Sailing Association |
| ISA | Infectious Salmon Anaemia |
| ISA | International Standard Atmosphere |
| ISA | International Security Affairs |
| ISA | International Society for Measurement and Control |
| ISA | Israel Securities Authority |
| ISA | Information Security and Assurance (international conference) |
| ISA | Industry Sector Analysis |
| ISA | Iowa Soybean Association |
| ISA | International Stuttering Association |
| ISA | Intrinsic Sympathomimetic Activity |
| ISA | Independent Safety Assessment |
| ISA | Intelligence Support Activity (US Army) |
| ISA | International Society of Arborists |
| ISA | Interactive Services Association |
| ISA | Israel Space Agency |
| ISA | Information Security Architecture |
| ISA | Interstellar Alliance (Babylon5) |
| ISA | International Stillbirth Alliance (Chicago, Illinois, USA) |
| ISA | International Space Agency (Star Trek) |
| ISA | Instituto Superior de Agricultura (Dominican Republic) |
| ISA | Instrumentation Society of America (Research Triangle Park, North Carolina) |
| ISA | Investment Savings Account |
| ISA | Investment Savings Account ( UK tax-free investment account) |
| ISA | Institut Supérieur d'Agriculture de Lille (French: Lille Higher Institute of Agriculture; Lille, France) |
| ISA | Information System Architecture |
| ISA | Integrated Services Architecture |
| ISA | Integrated Starter-Alternator |
| ISA | Importer Self-Assessment Program |
| ISA | International Service Assessment |
| ISA | Incest Survivors Anonymous |
| ISA | International Spa Association |
| ISA | International Strategic Alliance |
| ISA | International School of the Americas (San Antonio, TX) |
| ISA | Interservice Support Agreement |
| ISA | International Society of Women Airline Pilots |
| ISA | Interconexión Eléctrica SA (Colombia) |
| ISA | Integrated Systems Analysts, Inc. |
| ISA | Integrated System Architecture |
| ISA | International Standards Association |
| ISA | Incomplete Stent Apposition |
| ISA | International Silk Association (East Rutherford, NJ) |
| ISA | Inertial Sensor Assembly |
| ISA | Interstage Adapter |
| ISA | Indian Society of Anaesthesiologists |
| ISA | Ionic Strength Adjuster |
| ISA | Israel Society of Anesthesiologists |
| ISA | International Synaesthesia Association |
| ISA | International Standardization Agreement |
| ISA | In Shaa' Allah (God Willing) |
| ISA | Islamic Shipowners' Association |
| ISA | Integrated Systems and Aerostructures (Northrop Grumman Corp.) |
| ISA | Indirect Speech Act (linguistics) |
| ISA | Ionic Self-Assembly |
| ISA | Integrated Safety Assessment |
| ISA | Irish Stammering Association |
| ISA | International School of Arizona |
| ISA | Ismaili Students Association |
| ISA | Institution of Surveyors, Australia Inc |
| ISA | Indian Set-Aside (grant) |
| ISA | Illinois Society of Anesthesiologists |
| ISA | Integrated Safety Approach |
| ISA | Iterative Sensitivity Adjustment |
| ISA | Integrated Stereo Amplifier |
| ISA | Individual Services Agreement |
| ISA | Inter-Service Agreement |
| ISA | Integrated Services Access |
| ISA | Innovative Signal Analysis |
| ISA | Indiana Society of Anesthesiologists |
| ISA | Interim Storage Area |
| ISA | Integrated Servo Actuator (hydraulic actuators with integrated control unit) |
| ISA | Indiana Sheep Association (Greenwood, IN) |
| ISA | Interviewing Service of America, Inc. (Van Nuys, CA) |
| ISA | Iso-Saccharinic Acid |
| ISA | Installation Support Agreement |
| ISA | Idaho Sheriffs' Association |
| ISA | Interrupt Storage Area |
| ISA | Indicator-Based Stall Avoidance |
| ISA | Incident Surprise Anomaly Report |
| ISA | Intermediate Staging Area |
| ISA | Installation Supply Activity |
| ISA | Information Science Associates |
| ISA | In-Depth Safety Analysis |
| ISA | Inductee Special Assignment |
| ISA | Intelligent Search Assistant |
| ISA | Information and Services Acquisition |
| ISA | Information Services Analysis |
| ISA | Integrated Support Area |
| ISA | Information Society Assessment (EU) |
| ISA | Integrated Support Activity |
| ISA | Installation Support Activity |
| ISA | Institute for Application-Oriented Software and Systems (GMD, Germany) |
| ISA | International Subscription Agencies Pty Ltd (now RoweCom Australia Pty Ltd) |
| ISA | Inprocess Sample Analysis |
| ISA | Iterative Statistics Algorithm |
| ISA | Ignition & Separation Assembly |
| ISA | Imaging Sensor Autoprocessor |
| ISA | Imaging/Imagery Sensor Autoprocessor |
| ISA | Intensive Support Allocations |
| ISA | Installation Supply Account |
| ISA | Instructor of Small Arms |
| ISA | Ideal Survey Attributes (relate to key success factors in instrument development & quality improvement) |
| ISA | Instantaneous Selection Algorithm |
| ISA | IETM Support Activity |
| ISA | IRS System Architecture |
| ISA | Information Superiority Assessment |
| ISA | International Shipmasters Association of the Great Lakes |
| ISA | Installation and Service Activity |
| ISA | Insurance Service Account (Northwestern Mutual; Milwaukee, WI) |
| ISA | Identifier Splitting Algorithm |
| ISA | Intrasystem Analysis |
| ISA | International Systems Associates, Ltd. |
| ISA | International Society of Andrology |
| ISA | Internet Safety Advocate |
| ISA | Internal Systems Administrator |
| ISA | International Studies Abroad (various locations) |
| ISA | International Sign Association (formerly National Electric Sign Association) |
| ISA | Iran Sanctions Act of 1996 |
| ISA | Independent Strategic Advisors (Atlanta, GA) |
| ISA | Internet Service Agentur GmbH (German: Internet Service Agency) |
| ISA | Invest in Sweden Agency |
| ISA | International Student Advisory (various locations) |
| ISA | Internet Security Appliance (software) |
| ISA | International Services Advertising |
| ISA | Institute for Study Abroad |