Final answer:
A secondary ceiling installed to create space for utilities or change room proportions is called a drop ceiling or suspended ceiling.
Step-by-step explanation:
The correct term for a secondary ceiling that is installed to provide space for piping or ductwork, or to alter the proportions of a room, is a drop ceiling or suspended ceiling. These types of ceilings hang below the main structural ceiling and are particularly common in commercial buildings.
A drop ceiling allows for easy access to ducts and wiring and can also improve the aesthetics of a room by creating a more proportional space or hiding damaged original ceilings.