System

A system is a collection of elements — building blocks, components, or other parts — organized together to serve a common purpose.

The term is deliberately broad. ISO/IEC 15288 defines systems as man-made, and possibly configured from any mix of hardware, software, data, humans, processes, procedures, facilities, and materials, while IEEE Std 1471:2000 extends the idea to any software-intensive system — one where software contributes essential influence to its design, construction, deployment, and evolution — to cover individual applications, subsystems, whole enterprises, and systems of systems alike.

"System" is most often shorthand for a software system, the thing whose architecture, quality, and behavior the rest of these entries are concerned with.