- 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.
Origin of atom
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|DAILY BEAST
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|Alex Suskind|October 14, 2014|DAILY BEAST
You have the atom, which has the neutron, the electron, the proton.
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|Alex Belth|August 2, 2014|DAILY BEAST
Each type of atom and molecule has its own unique spectrum, according to the rules of quantum mechanics.
"I don't believe there's an atom of meaning in it," ventured Alice.Alice in Wonderland|Lewis Carroll
She regarded that swinging window of heavy plate glass with an anxiety of desire that thrilled through every atom of her blood.When the Cock Crows|Waldron Baily
Will you tell our readers what you think of using the atom bomb against the grass?Greener Than You Think|Ward Moore
The mass of each particle is, according to the latest and finest measurements 1/1845 of that of an atom of hydrogen.The Outline of Science, Vol. 1 (of 4)|J. Arthur Thomson
The señora looked again at the atom; she held out a timorous finger to him.Leerie|Ruth Sawyer
- 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
Word Origin 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.