atomとは 意味・読み方・使い方

別の表記

• atomus (廃れた用法)

語源

From Middle English attome, from Middle French athome, from Latin atomus (“smallest particle”), from Ancient Greek ἄτομος (átomos, “indivisible”), from ἀ- (a-, “not”) +‎ τέμνω (témnō, “I cut”).

発音

• IPA^(key): /ˈætəm/
• 韻: -ætəm
• Homophone: Adam (in dialects with flapping)
• ハイフネーション: at‧om

名詞

atom (複数形 atoms)

1. (chemistry, physics) The smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons. [from 16th c.]

   Meronyms: proton, neutron, electron

   • 2013 September–October, Katie L. Burke, “In the news: Photosynthesis precursor”, in American Scientist‎^[1], archived from the original on 13 April 2016:

     Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis: the ability to convert water and carbon dioxide into carbohydrates and waste oxygen using solar energy. The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the water-oxidizing complex, made up of manganese atoms and a calcium atom.

2. (history of science) A hypothetical particle posited by Greek philosophers as an ultimate and indivisible component of matter. [from 15th c.]
3. (now generally regarded figuratively) The smallest, indivisible constituent part or unit of something. [from 17th c.]
   • 1835, John Ross; James Clark Ross, “Chapter XXXIV. Labour in Cutting through the Ice—Become Fixed for the Winter—Summary of the Month.”, in Narrative of a Second Voyage in Search of a North-west Passage, and of a Residence in the Arctic Regions, during the Years 1829, 1830, 1831, 1832, 1833; by Sir John Ross, C.B., K.S.A., K.C.S., &c. &c. Captain in the Royal Navy. Including the Reports of Commander (now Captain) J. C. Ross, R.N., F.R.S., F.L.S., &c. and the Discovery of the Northern Magnetic Pole, Philadelphia, Pa.: E. A. Carey & A. Hart; Baltimore, Md.: Carey, Hart & Co., OCLC 936607945, pages 283–284:

     Towards the following morning, the thermometer fell to 5°; and at daylight, there was not an atom of water to be seen in any direction.

   • 1863, Charles Reade, Hard Cash‎^[2]:

     But at this critical moment the pirate astern sent a mischievous shot and knocked one of the men to atoms at the helm.

4. (philosophy) In logical atomism, a fundamental fact that cannot be further broken down.
5. (historical) The smallest medieval unit of time, equal to fifteen ninety-fourths of a second. [from 10th c.]
6. A mote of dust in a sunbeam. [from 16th c.]
7. A very small amount; a whit. [from 17th c.]
   • 1873, “Pansy” [pseudonym; Isabella Macdonald Alden], “A Double Crisis”, in Three People, Cincinnati, Oh.: Western Tract and Book Society, 176 Elm Street, OCLC 29248538, page 325:

     "Doctor, tell me one word more," said Theodore, quivering with suppressed emotion. "How do you think it will end?" / "I have hardly the faintest atom of hope," answered this honest, earnest man.

   • 1945 August 17, George Orwell [pseudonym; Eric Arthur Blair], chapter 1, in Animal Farm […], London: Secker & Warburg, OCLC 3655473:

     Now, comrades, what is the nature of this life of ours? Let us face it, our lives are miserable, laborious, and short. We are born, we are given just so much food as will keep the breath in our bodies, and those of us who are capable of it are forced to work to the last atom of our strength; and the very instant that our usefulness has come to an end we are slaughtered with hideous cruelty. No animal in England knows the meaning of happiness or leisure after he is a year old. No animal in England is free. The life of an animal is misery and slavery: that is the plain truth.

8. (computing, programming, Lisp) An individual number or symbol, as opposed to a list; a scalar value. [from 20th c.]
9. (mathematics) A non-zero member of a partially ordered set that has only zero below it (assuming that the poset has a least element, its "zero"). [from 20th c.]

   Antonym: coatom

   In a Venn diagram, an atom is depicted as an area circumscribed by lines but not cut by any line.

10. (mathematics, set theory) An element of a set that is not itself a set; an urelement. [from 20th c.]
11. (Canada, usually attributive) An age group division in hockey for nine- to eleven-year-olds.

同意語

• See also Thesaurus:atom
• (small amount): see also Thesaurus:modicum.

派生語

派生した語

• → Swahili: atomi

参考

• ⚛
• chemical element

Further reading

• atom on Wikipedia.

アナグラム

• Amto, Mato, Mota, TMAO, atmo, moat, mota, toma