- the smallest component of an element having the chemical properties of the element, consisting of a nucleus containing combinations of neutrons and protons and one or more electrons bound to the nucleus by electrical attraction; the number of protons determines the identity of the element.
- an atom with one of the electrons replaced by some other particle: muonic atom; kaonic atom.
- Energy. this component as the source of nuclear energy.
- a hypothetical particle of matter so minute as to admit of no division.
- anything extremely small; a minute quantity.
Origin of atom
SynonymsSee more synonyms on Thesaurus.com
Examples from the Web for atom
Check: “This atom smashing business is going to herald the final victory of the machine.”Mailer’s Letters Pack a Punch and a Surprising Degree of Sweetness
Ronald K. Fried
December 14, 2014
Releasing a new issue was like dropping an atom bomb on the industry.It Was All a Dream: Drama, Bullshit, and the Rebirth of The Source Magazine
October 14, 2014
You have the atom, which has the neutron, the electron, the proton.‘Crazy’ Harlem Pastor Hates on Obama and Gays
September 28, 2014
A face in a sea of faces, how could you know he hid among them like Oppenheimer, building a lab to split the atom.The Stacks: How Leonard Chess Helped Make Muddy Waters
August 2, 2014
Each type of atom and molecule has its own unique spectrum, according to the rules of quantum mechanics.SAMI Is Like Google Earth for the Universe
Matthew R. Francis
July 27, 2014
The ion differs from the molecule, the corpuscle and the atom in that it is an ion.The Devil's Dictionary
Fictions or realities, could they survive the touchstone of this atom of common sense?The Uncommercial Traveller
It wad but raise a strife atween the twa, ohn dune an atom o' guid.Heather and Snow
Even the good things that the atom had brought were destroyed in the panic that ensued.Now We Are Three
Joe L. Hensley
An atom of any kind is not the inert thing it has been supposed to be, for it can do something.The Machinery of the Universe
Amos Emerson Dolbear
- the smallest quantity of an element that can take part in a chemical reaction
- this entity as a source of nuclear energythe power of the atom See also atomic structure
- any entity regarded as the indivisible building block of a theory
- the hypothetical indivisible particle of matter postulated by certain ancient philosophers as the fundamental constituent of matterSee also atomism
- a very small amount or quantity; minute fragmentto smash something to atoms; there is not an atom of truth in his allegations
Word Origin and History for atom
late 15c., as a hypothetical indivisible body, the building block of the universe, from Latin atomus (especially in Lucretius) "indivisible particle," from Greek atomos "uncut, unhewn; indivisible," from a- "not" + tomos "a cutting," from temnein "to cut" (see tome). An ancient term of philosophical speculation (in Leucippus, Democritus), revived 1805 by British chemist John Dalton. In late classical and medieval use also a unit of time, 22,560 to the hour. Atom bomb is from 1945 as both a noun and a verb; cf. atomic.
- A unit of matter, the smallest unit of an element, having all the characteristics of that element and consisting of a dense, central, positively charged nucleus surrounded by a system of electrons. The entire structure has an approximate diameter of 10-8 centimeter and characteristically remains undivided in chemical reactions except for limited removal, transfer, or exchange of certain electrons.
- This unit regarded as a source of nuclear energy.
- A part or particle considered to be an irreducible constituent of a specified system.
- The irreducible, indestructible material unit postulated by ancient atomism.
- An extremely small part, quantity, or amount.
- The smallest unit of an element, consisting of at least one proton and (for all elements except hydrogen) one or more neutrons in a dense central nucleus, surrounded by one or more shells of electrons. In electrically neutral atoms, the number of protons equals the number of electrons. Atoms remain intact in chemical reactions except for the removal, transfer, or exchange of certain electrons. Compare compound. See also ion isotope orbital.