or stoicheiometry or stoechiometry (ˌstɔɪkɪˈɒmɪtrɪ)
noun
the branch of chemistry concerned with the proportions in which elements are combined in compounds and the quantitative relationships between reactants and products in chemical reactions
Word origin
C19: from Greek stoikheion element + -metry
stoichiometry in American English
(ˌstɔɪkiˈɑmətri)
noun
1.
the determination of the proportions in which chemical elements combine or are produced and the weight relations in any chemical reaction
2.
the branch of chemistry dealing with the relationships of elements entering into and resulting from combination, esp. with quantitative relationships