1. A large quantity or amount: Much has been written. 2. Something great or remarkable: The campus wasn't much to look at. (in combinations such as 'as much', 'this much') Used to indicate, demonstrate or compare the quantity of something. Much is used as an adjective or adverb, but it always means a large quantity, extent, or degree. When something hurts very much, it's very painful, and when your friend says your gift is very much appreciated, she's emphasizing how happy it made her. “Much” refers to a large amount of an uncountable noun (e.g., much water, much time). “Many” refers to a large number of countable nouns (e.g., many books, many people). MUCH definition: 1. a large amount or to a large degree: 2. a far larger amount of something than you want or need…. Learn more. MUCH definition: great in quantity, measure, or degree. See examples of much used in a sentence. The meaning of MUCH is great in quantity, amount, extent, or degree. How to use much in a sentence.