Noun

(categories)

A group, often named or numbered, to which items are assigned based on similarity or defined criteria.

*

The traditional way of describing the similarities and differences between constituents is to say that they belong to categories'' of various types. Thus, words like ''boy'', ''girl'', ''man'', ''woman'', etc. are traditionally said to belong to the category''' of Nouns, whereas words like ''a'', ''the'', ''this'', and ''that'' are traditionally said to belong to the ' category of Determiners.

This steep and dangerous climb belongs to the most difficult category .

I wouldn't put this book in the same category as the author's first novel.

(mathematics) A collection of objects, together with a transitively closed collection of composable arrows between them, such that every object has an identity arrow, and such that arrow composition is associative.

One well-known category has sets as objects and functions as arrows.

Just as a monoid consists of an underlying set with a binary operation "on top of it" which is closed, associative and with an identity, a category consists of an underlying digraph with an arrow composition operation "on top of it" which is transitively closed, associative, and with an identity at each object. In fact, a category's composition operation, when restricted to a single one of its objects, turns that object's set of arrows (which would all be loops) into a monoid.

Noun

(en noun)

A group or bunch of several discrete items that are close to each other.

a cluster of islands

* Spenser

Her deeds were like great clusters of ripe grapes, / Which load the bunches of the fruitful vine.

*{{quote-book, year=1907, author=

, chapter=7, title= The Dust of Conflict , passage=Then there was no more cover, for they straggled out, not in ranks but clusters , from among orange trees and tall, flowering shrubs

*{{quote-news, year=2011, date=December 29, author=Keith Jackson, work=Daily Record

, title= SPL: Celtic 1 Rangers 0 , passage=Charlie Mulgrew’s delicious deadball delivery was attacked by a cluster of green and white shirts at McGregor’s back post but Ledley got up higher and with more purpose than anyone else to thump a header home from five yards.}}

*{{quote-magazine, year=2013, month=May-June, author= William E. Conner

, title= An Acoustic Arms Race , volume=101, issue=3, page=206-7, magazine=(American Scientist) , passage=Earless ghost swift moths become “invisible” to echolocating bats by forming mating clusters close (less than half a meter) above vegetation and effectively blending into the clutter of echoes that the bat receives from the leaves and stems around them.}}

A number of individuals grouped together or collected in one place; a crowd; a mob.

* Milton

As bees / Pour forth their populous youth about the hive / In clusters .

* Shakespeare

We loved him; but, like beasts / And cowardly nobles, gave way unto your clusters , / Who did hoot him out o' the city.

(astronomy) A group of galaxies or stars that appear near each other.

(music) A secundal chord of three or more notes.

(phonetics) A group of consonants.

(computing) A group of computers that work together.

(computing) A logical data storage unit containing one or more physical sectors (see block).

(statistics) A significant subset within a population.

(military) Set of bombs or mines.

(army) A small metal design that indicates that a medal has been awarded to the same person before.

An ensemble of bound atoms or molecules, intermediate in size between a molecule and a bulk solid.