subinstrument
A subinstrument is a component or a specialized piece of equipment that is part of a larger, more complex instrument. Think of it as a smaller tool designed to perform a specific function within the overall operation of the main instrument. Subinstruments are often integrated into a primary instrument to enhance its capabilities or to measure a particular parameter that the main instrument might not be able to detect on its own.
For instance, in a telescope, a subinstrument could be a spectrograph, which analyzes the light collected by