Groupとは 意味・読み方・使い方

語源

From French groupe (“cluster, group”), from Italian gruppo, groppo (“a knot, heap, group, bag (of money)”), from Vulgar Latin *cruppo, Renaissance Latin grupus, from Frankish *krupp, from Proto-Germanic *kruppaz (“lump, round mass, body, crop”), from Proto-Indo-European *grewb- (“to crumple, bend, crawl”).

In the “group theory” sense, calqued from French groupe, a term coined by the young French mathematician Évariste Galois in 1830.

Cognate with German Kropf (“crop, craw, bunch”); 古期英語 cropp, croppa (“cluster, bunch, sprout, flower, berry, ear of corn, crop”) (whence English crop); Dutch krop (“craw”), Icelandic kroppr (“hump, bunch”). Doublet of crop and croup.

発音

• enPR: gro͞op, IPA: /ɡɹuːp/
• 韻: -uːp

名詞

group (plural groups)

1. A number of things or persons being in some relation to one another.
   • 1918, W[illiam] B[abington] Maxwell, chapter V, in The Mirror and the Lamp, Indianapolis, Ind.: The Bobbs-Merrill Company, →OCLC:

     Then everybody once more knelt, and soon the blessing was pronounced. The choir and the clergy trooped out slowly, […] , down the nave to the western door. […] At a seemingly immense distance the surpliced group stopped to say the last prayer.

   • 2013 July 19, Peter Wilby, “Finland spreads word on schools”, in The Guardian Weekly, volume 189, number 6, page 30:

     Imagine a country where children do nothing but play until they start compulsory schooling at age seven. Then, without exception, they attend comprehensives until the age of 16. Charging school fees is illegal, and so is sorting pupils into ability groups by streaming or setting.

   there is a group of houses behind the hill;  he left town to join a Communist group

   A group of people is/are gathering in front of the Parliament to demonstrate against the Prime Minister's proposals.

2. (group theory) A set with an associative binary operation, under which there exists an identity element, and such that each element has an inverse.
   • 1977, Roger C. Lyndon, Paul E. Schupp, Combinatorial Group Theory, Springer, page 192:

     Throughout this section, we shall assume the existence of finitely presented groups with unsolvable word problem.

   • 1992, Svetlana Katok, Fuchsian Groups, University of Chicago Press, page 112:

     In this chapter we give some examples of Fuchsian groups. The most interesting and important ones are the so-called "arithmetic" Fuchsian groups, i.e., discrete subgroups of PSL(2,R) obtained by some "arithmetic" operations. One such construction we have already seen: if we choose all matrices of SL(2,R) with integer coefficients, then the corresponding elements of PSL(2,R) form the modular group PSL(2,Z).

   • 2007, Zhong-Qi Ma, Group Theory for Physicists, World Scientific, page 277,

     In Chap. 4 the fundamental concepts on Lie groups have been introduced through the SO(3) group and its covering group SU(2).

3. (geometry, archaic) An effective divisor on a curve.
4. A (usually small) group of people who perform music together.

   Did you see the new jazz group?

5. (astronomy) A small number (up to about fifty) of galaxies that are near each other.
6. (chemistry) A column in the periodic table of chemical elements.
7. (chemistry) A functional group.

   Nitro is an electron-withdrawing group.

8. (sociology) A subset of a culture or of a society.
9. (military) An air force formation.
10. (geology) A collection of formations or rock strata.
11. (computing) A number of users with the same rights with respect to accession, modification, and execution of files, computers and peripherals.
12. An element of an espresso machine from which hot water pours into the portafilter.
13. (music) A number of eighth, sixteenth, etc., notes joined at the stems; sometimes rather indefinitely applied to any ornament made up of a few short notes.
14. (sports) A set of teams playing each other in the same division, while not during the same period playing any teams that belong to other sets in the division.
    • 2012 October 15, Sid Lowe, “Spain aim to take 'very big step' towards 2014 World Cup against France”, in The Guardian:

      It is the third of eight matches that Spain will play in Group I, but the coach Vicente del Bosque has described it as being more akin to the first leg of a cup semi-final.

15. (business) A commercial organization.

同意語

• (number of things or persons being in some relation to each other): collection, set
• (people who perform music together): band, ensemble
• See also Thesaurus:group

上位語

• (in group theory): monoid

下位語

派生語

派生した語

参照

• group on Wikipedia.Wikipedia

動詞

group (third-person singular simple present groups, present participle grouping, simple past and past participle grouped)

1. (transitive) To put together to form a group.

   group the dogs by hair colour

2. (intransitive) To come together to form a group.
   • 2021 October 1, Calder Katyal, “Schools Need to Undo the Damage of Pods”, in The Atlantic‎:

     For many people forming pods last year, finding compatible people to group with was not a cost but a goal.

同意語

• (put together to form a group): amass, categorise/categorize, classify, collect, collect up, gather, gather together, gather up; see also Thesaurus:round up
• (come together to form a group): assemble, begather, foregather, throng; see also Thesaurus:assemble

派生語

• groupable

Further reading

• “group”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.
• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “group”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.