An atom is the smallest amount of a substance that can take part in a chemical reaction.
A methane molecule is composed of one carbon atom attached to four hydrogens.
Synonyms: particle, bit, spot, trace More Synonyms of atom
atom in British English
(ˈætəm)
noun
1.
a.
the smallest quantity of an element that can take part in a chemical reaction
b.
this entity as a source of nuclear energy
the power of the atom
See also atomic structure
2.
any entity regarded as the indivisible building block of a theory
3.
the hypothetical indivisible particle of matter postulated by certain ancient philosophers as the fundamental constituent of matter
See also atomism
4.
a very small amount or quantity; minute fragment
to smash something to atoms
there is not an atom of truth in his allegations
Word origin
C16: via Old French and Latin, from Greek atomos (n), from atomos (adj) that cannot be divided, from a-1 + temnein to cut
atom in American English
(ˈætəm)
noun
1. Obsolete
any of the indivisible particles postulated by philosophers as the basic component of all matter
2.
a tiny particle of anything; jot
3. Chemistry and Physics
any of the smallest particles of an element that combine with similar particles of other elements to produce compounds: atoms combine to form molecules, and consist of a complex arrangement of electrons revolving about a positively charged nucleus containing (except for hydrogen) protons and neutrons and other particles
Idioms:
the atom
Word origin
ME attome < OFr atome < L atomus < Gr atomos, uncut, indivisible, atom < a-, not + tomos < temnein, to cut: see -tomy
Examples of 'atom' in a sentence
atom
The party of international solidarity, Nato and the atom bomb.
Times, Sunday Times (2016)
The future of the atom bomb was still in doubt.
Grenville, J. A. S. The Collins History of the World in the 20th Century (1994)
Within a molecule atoms occur in fixed proportions.
McCahill, T. A. Biology Basic Facts (1982)
The chemical atoms belonging to these groups are those of the elements present in the compound.
Thompkins, Peter, Bird, Christopher Secrets of the Soil (1990)
What was true of splitting the atom is true of modifying the genes in a human embryo.
Times, Sunday Times (2016)
Zinc atoms have a looser hold on their electrons than carbon atoms do.
Schneider, Hermann & Schneider, Leo The Harper Dictionary of Science in Everyday Language (1988)
What is more they can only study one atom at a time.
Times, Sunday Times (2013)
These combinations of atoms are called molecules.
Youngson, Dr. Robert The Antioxidant Health Plan (1994)
Want to know how to split the atom and make a bomb?
Times, Sunday Times (2012)
The skeleton on which the structure of life is built is made of carbon atoms.
Holford, Patrick The Family Nutrition Workbook (1988)
The resulting flakes were one atom thick but very strong.
Times, Sunday Times (2016)
Now come down to the scale of molecules and atoms and meet two surprises.
Schneider, Hermann & Schneider, Leo The Harper Dictionary of Science in Everyday Language (1988)
The splitting of the atom meant the dawn of the nuclear age.
Times, Sunday Times (2012)
Sitting at the centre of this molecule chain is a string of carbon atoms.
Erdmann, Robert & Jones, Meirion Fats, Nutrition and Health (1991)
It is the kinetic energy of the atoms and molecules in a body.
Chapman, C. & Horsley, M. & Small, E. Technology Basic Facts (1990)
Each of the carbon atoms is capable of holding on to four additional atoms.
Chaitow, Leon The Beat Fatigue Workbook - how to identify the causes (1988)
What was it that was moving the atoms of elements to put out claws with which to grasp other elements?
Thompkins, Peter, Bird, Christopher Secrets of the Soil (1990)
Most organic molecules consist of a kind of basic structure of carbon atoms to which small clusters of other atoms are attached.
Youngson, Dr. Robert The Antioxidant Health Plan (1994)
Whisper this but when it comes to splitting the atom, they are better than us.
The Sun (2010)
I read about and faced up to the atom bomb.
Rowbotham, Sheila The Past is Before Us - feminism in action since the 1960s (1989)
Tiny amounts of a mineral can be punched out with a laser beam, and its constituent elements counted almost atom by atom.
Richard Fortey THE EARTH: An Intimate History (2004)
Destruction has been brought to an area 160 times larger than that hit by the Hiroshima atom bomb.
Times, Sunday Times (2007)
At one time we thought the atom was the smallest unit of the universe, and now we're finding universes within it.
Christianity Today (2000)
A small atom would now measure less than half a centimetre and the DNA molecule would be a few centimetres across.
The Times Literary Supplement (2013)
In other languages
atom
British English: atom /ˈætəm/ NOUN
An atom is the smallest possible amount of a chemical element.
American English: atom
Arabic: ذَرَّة
Brazilian Portuguese: átomo
Chinese: 原子
Croatian: atom
Czech: atom
Danish: atom
Dutch: atoom
European Spanish: átomo
Finnish: atomi
French: atome
German: Atom
Greek: άτομο
Italian: atomo
Japanese: 原子
Korean: 원자
Norwegian: atom
Polish: atom
European Portuguese: átomo
Romanian: atom
Russian: атом
Latin American Spanish: átomo
Swedish: atom
Thai: อะตอม
Turkish: atom
Ukrainian: атом
Vietnamese: nguyên tử
All related terms of 'atom'
anti-atom
an atom composed of antiparticles , in which the nucleus contains antiprotons with orbiting positrons
atom bomb
→ atomic bomb
gram atom
an amount of an element equal to its atomic weight expressed in grams : now replaced by the mole
the atom
nuclear energy
muonic atom
an atom in which an orbiting electron has been replaced by a muon
atom smasher
→ accelerator (sense 3 )
Rutherford atom
the atom postulated as analogous to the solar system, with electrons revolving around a small, central, positive nucleus that constitutes practically the entire mass of the atom
atomic bomb
An atomic bomb or an atom bomb is a bomb that causes an explosion by a sudden release of energy that results from splitting atoms.
accelerator
The accelerator in a car or other vehicle is the pedal which you press with your foot in order to make the vehicle go faster.
Chinese translation of 'atom'
atom
(ˈætəm) (Phys)
n(c)
原子 (yuánzǐ) (个(個), gè)
(noun)
Definition
a very small amount
one carbon atom attached to four hydrogens
Synonyms
particle
Particles of food can get stuck between the teeth.
bit
a bit of cake
spot
trace
Wash them in cold water to remove all traces of sand.
scrap
a fire fuelled by scraps of wood
molecule
a molecule of sulfur trioxide
grain
a grain of sand
dot
a small black dot in the middle
fragment
She read everything, digesting every fragment of news.
fraction
shred
There is not a shred of truth in this story.
crumb
I stood up, brushing crumbs from my trousers.
mite
jot
It doesn't affect my judgement one jot.
speck
He leaned forward and brushed a speck of dust off his shoes.
morsel
a delicious little morsel of meat
mote
Dust motes swirled in the sunlight.
whit
It does not make one whit of difference what we do.