enormousness

Synonyms: enormous, immense, huge, gigantic, colossal, mammoth, tremendous, gargantuan, vast
These adjectives describe what is extraordinarily large. Enormous suggests a marked excess beyond the norm in size, amount, or degree: an enormous boulder.
Immense refers to boundless or immeasurable size or extent: an immense sky.
Huge especially implies greatness of size or capacity: a huge tanker.
Gigantic refers to size likened to that of a giant: a gigantic redwood tree.
Colossal suggests a hugeness that elicits awe or taxes belief: a valley ringed by colossal mountains.
Mammoth is applied to something of unwieldy hugeness: "mammoth stone figures in ... buckled eighteenth-century pumps, the very soles of which seem mountainously tall" (Cynthia Ozick).
Tremendous suggests awe-inspiring or fearsome size: a tremendous waterfall.
Gargantuan stresses greatness of size or capacity and often suggests extravagance or excess: "Dense schools of menhaden ... slurp up enormous quantities of plankton and detritus like gargantuan vacuum cleaners" (H. Bruce Franklin).
Vast refers to greatness of extent, size, area, or scope, and is often applied to what inspires a sense of grandeur or awe: "Another vast mountain of darkness rose, towering up like a wave that should engulf the world" (J.R.R. Tolkien).