Does 'Stoichiometry' refer to the mole ratio of atoms in compounds and the mole ratio of compounds involved in chemical reactions?
That's right -- stoichiometry is a field which uses these numbers and the relationships between reactants and products, but not the numbers itself. The mole ratio is just the mole ratio, whereas stoichiometry is the entire discipline of using mole ratios to calculate relative quantities of reactants and products in reactions.