The definition of an atom is the smallest component of an element, characterized by a sharing of the chemical properties of the element and a nucleus with neutrons, protons and electrons.
Hydrogen and helium are examples of elements that have an atom.
See atom in Webster's New World College Dictionary
Origin: ME attome < OFr atome < L atomus < Gr atomos, uncut, indivisible, atom < a-, not + tomos < temnein, to cut: see -tomy
See atom in American Heritage Dictionary 4
Origin: Middle English attome
Origin: , from Latin atomus
Origin: , from Greek atomos, indivisible, atom
Origin: : a-, not; see a-1
Origin: + tomos, cutting (from temnein, to cut; see tem- in Indo-European roots).
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