Final answer:
The cellular building units for construction mentioned in the question are known as structural clay tile, commonly used in building infrastructure for its durability and protective qualities.
Step-by-step explanation:
The cellular building units made of fired clay, concrete, or gypsum, used for building walls, floors, roofs, or fireproofing steelwork are known as structural clay tile. These materials have been an important part of construction for millennia, being utilized in various forms from mud bricks in Mesopotamia to Cyclopean masonry in Mycenaean architecture. Modern use of materials like concrete and gypsum board has evolved to maximize benefits such as thermal protection, load reduction, and durability.