category

[kat-i-gawr-ee, -gohr-ee] /ˈkæt ɪˌgɔr i, -ˌgoʊr i/
noun, plural categories.
1.
any general or comprehensive division; a class.
2.
a classificatory division in any field of knowledge, as a phylum or any of its subdivisions in biology.
3.
Metaphysics.
  1. (in Aristotelian philosophy) any of the fundamental modes of existence, such as substance, quality, and quantity, as determined by analysis of the different possible kinds of predication.
  2. (in Kantian philosophy) any of the fundamental principles of the understanding, as the principle of causation.
  3. any classification of terms that is ultimate and not susceptible to further analysis.
4.
categories, Also called Guggenheim. (used with a singular verb) a game in which a key word and a list of categories, as dogs, automobiles, or rivers, are selected, and in which each player writes down a word in each category that begins with each of the letters of the key word, the player writing down the most words within a time limit being declared the winner.
5.
Mathematics. a type of mathematical object, as a set, group, or metric space, together with a set of mappings from such an object to other objects of the same type.
6.
Grammar, part of speech.
Origin
1580-90; < Late Latin catēgoria < Greek katēgoría accusation (also, kind of predication), equivalent to katḗgor(os) accuser, affirmer (katēgor(eîn) to accuse, affirm, literally, speak publicly against, equivalent to kata- cata- + -agoreîn to speak before the agora + -os noun suffix) + -ia -y3
Synonyms
1. group, grouping, type.
Examples from the web for category
  • To begin select an advertiser type and ad category below.
  • To search, type in a keyword and/or choose a category.
  • The dignity bestowed upon the dream by older psychological authors falls chiefly in this category.
  • But it is already plain that middle life will find him in that category.
  • In the second and more usual sense, wealth is the collective name for a category of goods.
  • In that category before anything else comes old age, to which all wish to attain, and at which all grumble when attained.
  • It belongs to the widespread tendency whereby a part of speech jumps its category.
  • As part of the lecture, he'll be screening pictures of his own garden and of other gardens that fit the same category.
  • Use the app to search for gifts by category, recipient, or price.
  • Both groups are well represented here, with the lists skewed toward those that are in the shrub or small tree category.
British Dictionary definitions for category

category

/ˈkætɪɡərɪ/
noun (pl) -ries
1.
a class or group of things, people, etc, possessing some quality or qualities in common; a division in a system of classification
2.
(metaphysics) any one of the most basic classes into which objects and concepts can be analysed
3.
  1. (in the philosophy of Aristotle) any one of ten most fundamental modes of being, such as quantity, quality, and substance
  2. (in the philosophy of Kant) one of twelve concepts required by human beings to interpret the empirical world
  3. any set of objects, concepts, or expressions distinguished from others within some logical or linguistic theory by the intelligibility of a specific set of statements concerning them See also category mistake
Word Origin
C15: from Late Latin catēgoria, from Greek katēgoria, from kategorein to accuse, assert
Word Origin and History for category
n.

1580s, from Middle French catégorie, from Late Latin categoria, from Greek kategoria "accusation, prediction, category," verbal noun from kategorein "to speak against; to accuse, assert, predicate," from kata "down to" (or perhaps "against;" see cata-) + agoreuein "to harangue, to declaim (in the assembly)," from agora "public assembly" (see agora). Original sense of "accuse" weakened to "assert, name" by the time Aristotle applied kategoria to his 10 classes of things that can be named.

category should be used by no-one who is not prepared to state (1) that he does not mean class, & (2) that he knows the difference between the two .... [Fowler]

category in Technology
theory
A category K is a collection of objects, obj(K), and a collection of morphisms (or "arrows"), mor(K) such that
1. Each morphism f has a "typing" on a pair of objects A, B written f:A->B. This is read 'f is a morphism from A to B'. A is the "source" or "domain" of f and B is its "target" or "co-domain".
2. There is a partial function on morphisms called composition and denoted by an infix ring symbol, o. We may form the "composite" g o f : A -> C if we have g:B->C and f:A->B.
3. This composition is associative: h o (g o f) = (h o g) o f.
4. Each object A has an identity morphism id_A:A->A associated with it. This is the identity under composition, shown by the equations
id__B o f = f = f o id__A.
In general, the morphisms between two objects need not form a set (to avoid problems with Russell's paradox). An example of a category is the collection of sets where the objects are sets and the morphisms are functions.
Sometimes the composition ring is omitted. The use of capitals for objects and lower case letters for morphisms is widespread but not universal. Variables which refer to categories themselves are usually written in a script font.
(1997-10-06)