Dictionary
Thesaurus
Reference
Translate
Web
Nearby Entries
atom - 9 dictionary results

at⋅om

[at-uhm]
–noun
1. Physics.
a. 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.
b. an atom with one of the electrons replaced by some other particle: muonic atom; kaonic atom.
2. Energy. this component as the source of nuclear energy.
3. a hypothetical particle of matter so minute as to admit of no division.
4. anything extremely small; a minute quantity.

Origin:
1350–1400; ME attomos, athomus < L atomus < Gk átomos, n. use of átomos undivided, equiv. to a- a- 6 + tomós divided, verbid of témnein to cut


4. shred, speck, scintilla, iota, jot, whit.
at·om   (āt'əm)   


(click for larger image in new window)
n.  
    1. A part or particle considered to be an irreducible constituent of a specified system.
    2. The irreducible, indestructible material unit postulated by ancient atomism.
    3. 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.
    4. This unit regarded as a source of nuclear energy. See Table at subatomic particle.
  1. An extremely small part, quantity, or amount.
  2. Physics & Chemistry
    1. 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.
    2. This unit regarded as a source of nuclear energy. See Table at subatomic particle.

[Middle English attome, from Latin atomus, from Greek atomos, indivisible, atom : a-, not; see a-1 + tomos, cutting (from temnein, to cut; see tem- in Indo-European roots).]

Atom

At"om\, n. [L. atomus, Gr. ?, uncut, indivisible; 'a priv. + ?, verbal adj. of ? to cut: cf. F. atome. See Tome.]

1. (Physics) (a) An ultimate indivisible particle of matter. (b) An ultimate particle of matter not necessarily indivisible; a molecule. (c) A constituent particle of matter, or a molecule supposed to be made up of subordinate particles.

Note: These three definitions correspond to different views of the nature of the ultimate particles of matter. In the case of the last two, the particles are more correctly called molecules. --Dana.

2. (Chem.) The smallest particle of matter that can enter into combination; one of the elementary constituents of a molecule.

3. Anything extremely small; a particle; a whit.

There was not an atom of water. --Sir J. Ross.

Atom

At"om\, v. t. To reduce to atoms. [Obs.] --Feltham.
Language Translation for : atom
Spanish: átomo,
German: das Atom,
Japanese: 原子

atom

A unit of matter; the smallest unit of a chemical element. Each atom consists of a nucleus, which has a positive charge, and a set of electrons that move around the nucleus. (See Bohr atom.)

Note: Atoms link together to form molecules.

atom 
1477, as a hypothetical body, the building block of the universe, from L. atomus (especially in Lucretius), from Gk. atomos "uncut," from a- "not" + tomos "a cutting," from temnein "to cut." An ancient term of philosophical speculation (in Leucippus, Democritus), revived 1805 by British chemist Dalton. Atomic is from 1678 as a philosophical term; scientific sense dates from 1811. Atomic energy first recorded 1906; atomic bomb first recorded 1914 in writings of H.G. Wells, who thought of it as a bomb "that would continue to explode indefinitely." Atom bomb is from 1945; Atomic Age is from 1945.
"When you can drop just one atomic bomb and wipe out Paris or Berlin, war will have become monstrous and impossible." [S. Strunsky, "Yale Review," January 1917]
Atomize "reduce a liquid to a fine mist" is from 1865; sense of "to destroy with atomic weapons" is from 1945.

Main Entry: at·om
Pronunciation: 'at-&m
Function: noun
: the smallest particle of an element that can exist either alone or in combination —atom·ic /&-'täm-ik/ adjectiveatom·i·cal·ly /-i-k(&-)lE/ adverb

atom at·om (āt'əm)
n.

  1. 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.
  2. This unit regarded as a source of nuclear energy.
  3. A part or particle considered to be an irreducible constituent of a specified system.
  4. The irreducible, indestructible material unit postulated by ancient atomism.
  5. An extremely small part, quantity, or amount.

a·tom'ic (ə-tŏm'ĭk) adj.

atom   (āt'əm)  Pronunciation Key 
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.
Search another word or see atom on Thesaurus | Reference