Meaning of law of diminishing marginal utility

law' of dimin'ishing mar'ginal util'ity

Pronunciation: [key]
— Econ. Econ.
  1. the law that for a single consumer the marginal utility of a commodity diminishes for each additional unit of the commodity consumed.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.