The scientific analysis of systems, and the interactions within them.

An electronic system used to store, process and display geographic information, especially maps

(computing) A person whose job is to perform systems analysis by being responsible for researching, planning and recommending software and system choices to meet an organization's business requirements.

(anatomy, immunology) The system that differentiates self from non-self and protects the body from foreign substances and pathogenic organisms by producing an immune response. It includes organs such as the thymus, the spleen and lymph nodes; tissue such as bone marrow, and lymphoid tissues such as the tonsils; cells such as lymphocytes including the B cells and T cells, and cell products such as antibodies.

(informal) Everything is ready.

(astronomy) The combined system or structure formed by all of the rings orbiting a planet

(anatomy) A system of organs for the purpose of digesting food.

(aeronautics) A device which warns the pilot that the aircraft may be in danger of collision with the ground.

(taxonomy) A coherent system of taxonomic judgements on circumscription and placement of the considered taxa. A taxonomic system is restricted to a large but limited part of the living world.

A navigation system that produces hyperbolic lines of position by the measurement of the difference in the time of reception, or the phase, of radio signals from multiple synchronized transmitters at fixed locations.