stoichiometry
noun
stoi·chi·om·e·try ˌstȯi-kē-ˈä-mə-trē 
1
: a branch of chemistry that deals with the application of the laws of definite proportions and of the conservation of mass and energy to chemical activity
2
a
: the quantitative relationship between constituents in a chemical substance
b
: the quantitative relationship between two or more substances especially in processes involving physical or chemical change
Example Sentences
Recent Examples on the Web The study relies on stoichiometry, which measures the elemental ratios that appear in the chemistry of cells and ecosystems. 
Natalie Elliot, Scientific American, 16 July 2021 If the regularity of chemical ratios within cells is a universal property of biological systems, here or anywhere else in the cosmos, then careful stoichiometry could be the key to eventually discovering life on an alien world. Natalie Elliot, Scientific American, 16 July 2021
Natalie Elliot, Scientific American, 16 July 2021 If the regularity of chemical ratios within cells is a universal property of biological systems, here or anywhere else in the cosmos, then careful stoichiometry could be the key to eventually discovering life on an alien world. Natalie Elliot, Scientific American, 16 July 2021 Word History
Etymology
Greek stoicheion element (from stoichos row) + English -metry; akin to Greek steichein to walk, go — more at stair
First Known Use
1807, in the meaning defined at sense 1
Medical Definition
stoichiometry
noun
stoi·chi·om·e·try ˌstȯi-kē-ˈäm-ə-trē
plural stoichiometries
1
: a branch of chemistry that deals with the application of the laws of definite proportions and of the conservation of mass and energy to chemical activity
2
a
: the quantitative relationship between constituents in a chemical substance
b
: the quantitative relationship between two or more substances especially in processes involving physical or chemical change