The definition of a molecule is the smallest amount of something, particularly of a chemical substance, that can exist on its own.
An example of a molecule are two atoms of hydrogen.
molecule definition by Webster's New World
the smallest particle of an element or compound that can exist in the free state and still retain the characteristics of the element or compound: the molecules of elements consist of one atom or two or more similar atoms; those of compounds consist of two or more different atoms
a small particle
Origin: French molécule ; from Modern Latin molecula, diminutive of Classical Latin moles, a mass: see mole
molecule definition by American Heritage Dictionary
The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces.
A small particle; a tiny bit.
Origin: French molécule, from New Latin mōlēcula, diminutive of Latin mōlēs, mass.
A group of two or more atoms linked together by sharing electrons in a chemical bond. Molecules are the fundamental components of chemical compounds and are the smallest part of a compound that can participate in a chemical reaction.