Meaning of law of multiple proportion

law' of mul'tiple propor'tion

Pronunciation: [key]
— Chem. Chem.
  1. the statement that where two elements can combine to form more than one compound, the ratio by weight of one element to a given weight of the second is usually a small whole number.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.