ISM

ISM is an acronym with several meanings across science, industry, and professional organizations. It can refer to the interstellar medium in astronomy, the practice of information security management, the Institute for Supply Management, or radio frequency bands reserved for industrial, scientific, and medical devices.

The interstellar medium is the matter that fills the space between stars in a galaxy. It consists of gas (primarily hydrogen and helium), dust, cosmic rays, and magnetic fields. It exists in distinct phases by temperature and density, from hot, ionized gas to cold molecular clouds. The interstellar medium serves as the reservoir for star formation and influences galactic evolution. It is studied through emission and absorption lines, such as the 21-centimeter hydrogen line and various molecular transitions.

Information security management is the discipline focused on protecting data and information systems. It involves governance, risk assessment, and the selection and implementation of security controls. Many organizations adopt an information security management system (ISMS) to ensure systematic handling of security risks, incident response, business continuity, and regular audits, often aligned with standards such as ISO/IEC 27001.

The Institute for Supply Management is a U.S. professional association for procurement and supply chain professionals, founded in 1915. It publishes standards, provides education, and grants certifications such as the CPSM. Its ISM Report On Business includes the Manufacturing PMI, a widely cited indicator of economic activity.

ISM bands refer to radio frequency ranges reserved for industrial, scientific, and medical devices. Devices may operate without a license within specified limits, subject to regulation to limit interference with other services.