apparati

Apparati is the plural form of apparatus, used in English to refer to multiple devices or pieces of equipment. The term apparatus itself comes from Latin apparatus, meaning tools, equipment, or a prepared arrangement. In contemporary English, apparatus is often treated as a mass noun or as a singular collective noun, with the common plural forms being apparatuses or, less commonly, apparati. Apparati as a Latin plural is more common in scholarly or technical writing and may be found in older texts.

In science, engineering, and medicine, apparati denotes the collection of instruments used for a particular procedure or experiment. Examples include laboratory apparati such as spectrometers, chromatographs, centrifuges, and optical benches, as well as industrial process apparati like reactors, heat exchangers, and control consoles. The term emphasizes the assembled nature of the tools rather than any single component.

Beyond physical devices, apparatus can also refer to an organized structure or system, such as the administrative apparatus of a government or the enforcement apparatus of an organization. In this sense, apparati would refer to multiple parts or subunits of such a system, though this plural usage is relatively rare outside formal writing.

See also: apparatus; equipment; instrumentation; lab equipment; plant and equipment.