Elements combine in definite proportions. Whewell.

Definite article (Gram.), the article the, which is used to designate a particular person or thing, or a particular class of persons or things; -- also called a definitive. See Definitive, n. - - Definite inflorescence. (Bot.) See Determinate inflorescence, under Determinate. -- Law of definite proportions (Chem.), the essential law of chemical combination that every definite compound always contains the same elements in the same proportions by weight; and, if two or more elements form more than one compound with each other, the relative proportions of each are fixed. Compare Law of multiple proportions, under Multiple.