QUANTUM [ˈkwɑɾ̃əm] ► audio Scrabble 18 Words With Friends 22 Definition noun a discrete amount of something that is analogous to the quantities in quantum theory. noun (physics) the smallest discrete quantity of some physical property that a system can possess (according to quantum theory). See all 34 words you can make from QUANTUM → 7-letter words Words starting with Q Words ending with M ← Unscramble different letters