What is the term for the failure of a system, equipment, or part to operate properly?

The term that refers to the failure of a system, equipment, or part to operate properly is "malfunction." This term specifically denotes that while the system or equipment may be intact and operational in some capacity, it is not performing according to its intended function or design requirements. This can result from various issues, including mechanical problems, electrical failures, or software errors, leading to a degradation in performance rather than a complete shutdown.

The other terms, while related, do not precisely capture the nuances of "malfunction." Breakdown usually refers to a more severe situation where equipment has entirely ceased functioning and cannot be used until repaired. Failure is a broader term that can denote either a complete stop or the inability to perform effectively. Defect implies a flaw or imperfection present in the design or manufacturing process that could lead to malfunction but does not inherently mean that the equipment has failed to operate at that moment. Understanding these distinctions helps clarify maintenance responses and strategies in building management.