a. Very great in size, extent, or amount.
b. Very great in scope or import: enormous influence.
2. Archaic Very wicked; heinous.
[From Latin ēnormis, unusual, huge, monstrous : ē-, ex-, ex- + norma, norm; see gnō- in the Appendix of Indo-European roots. Sense 2, from Middle English enormious, from Latin ēnormis.]
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).
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.