Dictionary Definition
OR
Noun
1 a state in northwestern United States on the
Pacific [syn: Oregon,
Beaver
State]
2 a room in a hospital equipped for the
performance of surgical operations; "great care is taken to keep
the operating rooms aseptic" [syn: operating
room, operating
theater, operating
theatre, surgery]
User Contributed Dictionary
Homophones
 awe (in nonrhotic accents)
 aw (in nonrhotic accents)
 oar
 ore
 o'er
Etymology 1
oþþe.Conjunction
 Connects at least two words, phrases, clauses, etc. that each could make a sentence true. In English, this is the "inclusive or." The "exclusive or" is "either...or".
 Logical union of two sets of values. There are two forms, an exclusive or and an inclusive or.
Synonyms
Translations
 Arabic:
 Aramaic:
 Basque: edo, ala
 Bosnian: ili
 Breton: pe
 Catalan: o, o bé
 Chinese: 或 (huò); 或者 (huòzhě)
 Croatian: ili
 Czech: nebo
 Danish: eller
 Dutch: of
 Esperanto: aŭ
 Finnish: tai (exclusive, only in affirmative clauses); vai (inclusive, only in question clauses)
 French: ou
 German: oder
 Gothic: vau
 Greek: ή, είτε
 Hindi: या (yā)
 Hungarian: vagy
 Icelandic: eða
 Ido: od, o
 Indonesian: atau
 Interlingua: o
 Italian: o, od (euphonic alt. form used before a vowel), oppure
 Japanese: 又は (または, matawa), あるいは (aruiwa), か (ka)
 Korean: 또는 (ttoneun)
 Latin: aut (exclusive), vel (inclusive)
 Latvian: vai
 Maltese: jew
 Norwegian: eller
 Novial: o
 Old English: hwæþer þe, oþþe
 Persian: (yā)
 Polish: albo, lub, czy
 Portuguese: ou
 Romanian: ori, sau
 Russian: или (íli)
 Serbian:
 Slovak: alebo, abo
 Slovene: ali
 Spanish: o, (before words beginning in 'o' or 'ho') u
 Swahili: au
 Swedish: eller
 Telugu: లేదా (léda)
 Turkish: veya
 Vietnamese: hay, hay là
Etymology 2
aurum via or.Noun
 The gold or yellow tincture on a coat of
arms.

 1909: The metals are gold and silver, these being termed "or" and "argent". — Arthur Charles FoxDavies, A Complete Guide to Heraldry
 1889: In engraving, "Or" is expressed by dots. — Charles Norton Elvin, A Dictionary of Heraldry

Alternative forms
Sometimes abbreviated as o. in heraldic contexts. Sometimes capitalized Or to distinguish use as a color from use as a conjunction.Related terms
 Au qualifier chemical symbol for gold
Translations
gold or yellow tincture
Adjective
 Of gold or yellow tincture on a coat of arms.
Synonyms
Translations
of yellow or gold tincture on a coat of arms
Basque
Noun
Catalan
Etymology
from aurum.Noun
French
Pronunciation
 /ɔʁ/
Etymology 1
aurum.Noun
frnoun mRelated terms
Etymology 2
ha hora, alteration of hac hora.See also
Norwegian
Etymology
From ǫlr, órirNoun
References
Dokumentasjonsprosjektet}}Norwegian Nynorsk
Etymology
FromOld English
Etymology
Extensive Definition
In logic
and mathematics, or,
also known as logical disjunction or inclusive disjunction is a
logical
operator that results in true whenever one or more of its
operands are true. In grammar, or is a coordinating
conjunction.
Definition
Logical disjunction is an operation
on two logical
values, typically the values of two propositions, that produces
a value of false if and only if both of its operands are false.
More generally a disjunction is a logical formula that can have one
or more literals
separated only by ORs. A single literal is often considered to be a
degenerate disjunction.
Truth table
The truth table of p OR q (also written as p\orq (logic), p  q (in Cfamily languages in computer programming), or p + q (electronics)) is as follows:Venn diagram
The Venn diagram of "p or q" (red is true)Properties
The following properties apply to
disjunction:
 associativity: a \lor (b \lor c) \equiv (a \lor b) \lor c
 commutativity: a \lor b \equiv b \lor a
 distributivity: (a \lor (b \land c)) \equiv ((a \lor b) \land (a \lor c))


 (a \land (b \lor c)) \equiv ((a \land b) \lor (a \land c))
 (a \lor (b \equiv c)) \equiv ((a \lor b) \equiv (a \lor c))

 idempotency: a \lor a \equiv a
 monotonicity: (a \rightarrow b) \rightarrow ((c \lor a) \rightarrow (c \lor b))


 (a \rightarrow b) \rightarrow ((a \lor c) \rightarrow (b \lor c))

 truthpreserving: The interpretation under which all variables are assigned a truth value of 'true' produces a truth value of 'true' as a result of disjunction.
 falsehoodpreserving: The interpretation under which all variables are assigned a truth value of 'false' produces a truth value of 'false' as a result of disjunction.
Symbol
The mathematical symbol for logical disjunction
varies in the literature. In addition to the word "or", the symbol
"\or", deriving from the Latin word vel for "or", is commonly used
for disjunction. For example: "A \or B " is read as "A or
B ". Such a disjunction is false if both A and B are
false. In all other cases it is true.
All of the following are disjunctions:
 A \or B
 \neg A \or B
 A \or \neg B \or \neg C \or D \or \neg E
The corresponding operation in set theory is the
settheoretic
union.
Applications in computer science
Operators corresponding to logical disjunction exist in most programming languages.Bitwise operation
Disjunction is often used for bitwise operations. Examples: 0 or 0 = 0
 0 or 1 = 1
 1 or 0 = 1
 1 or 1 = 1
 1010 or 1100 = 1110
The or operator can be used to set bits in a
bitfield to 1, by
oring the field with a constant field with the relevant bits set
to 1.
Logical operation
Many languages distinguish between bitwise and logical disjunction by providing two distinct operators; in languages following C, bitwise disjunction is performed with the single pipe () and logical disjunction with the double pipe () operators.Logical disjunction is usually shortcircuited;
that is, if the first (left) operand evaluates to true then the
second (right) operand is not evaluated. The logical disjunction
operator thus usually constitutes a sequence
point.
Although in most languages the type of a logical
disjunction expression is boolean and thus can only have the value
true or false, in some (such as
Python and JavaScript) the
logical disjunction operator returns one of its operands; the first
operand if it evaluates to a true value, and the second operand
otherwise.
Union
The union used in set theory is defined in terms of a logical disjunction: x ∈ A ∪ B if and only if (x ∈ A) ∨ (x ∈ B). Because of this, logical disjunction satisfies many of the same identities as settheoretic union, such as associativity, commutativity, distributivity, and de Morgan's laws.Notes
 Boole, closely following analogy with ordinary mathematics, premised, as a necessary condition to the definition of "x + y", that x and y were mutually exclusive. Jevons, and practically all mathematical logicians after him, advocated, on various grounds, the definition of "logical addition" in a form which does not necessitate mutual exclusiveness.
See also
 Exclusive disjunction
 Affirming a disjunct
 Bitwise OR
 Boolean algebra (logic)
 Boolean algebra topics
 Boolean domain
 Boolean function
 Booleanvalued function
 Disjunctive syllogism
 Disjunction elimination
 Disjunction introduction
 Firstorder logic
 Logical graph
 Logical value
 Operation
 Operator
 OR gate
 Propositional calculus
External links
or in Bulgarian: Логическа дизюнкция
or in Czech: Disjunkce
or in German: Disjunktion
or in Estonian: Disjunktsioon
or in Spanish: Disyunción lógica
or in Esperanto: Logika aŭo
or in French: Disjonction logique
or in Korean: 논리합
or in Indonesian: Logika disjungsi
or in Italian: Disgiunzione inclusiva
or in Hebrew: או (לוגיקה)
or in Lithuanian: Disjunkcija
or in Macedonian: Логичка дисјункција
or in Dutch: Logische disjunctie
or in Japanese: 論理和
or in Norwegian: Inklusiv disjunksjon
or in Polish: Alternatywa
or in Portuguese: Disjunção lógica
or in Simple English: Inclusive
disjunction
or in Slovak: Disjunkcia (logika)
or in Serbian: Дисјункција
or in Swedish: Disjunktion (logik)
or in Thai: การเลือกเชิงตรรกศาสตร์
or in Ukrainian: Диз'юнкція
(логічна)
Synonyms, Antonyms and Related Words
achievement, alerion, and/or, animal charge,
annulet, argent, armorial bearings,
armory, arms, aureate, aureateness, auric, azure, bandeau, bar, bar sinister, baton, bearings, beige, bend, bend sinister, billet, blazon, blazonry, bordure, broad arrow, buff, buffyellow, cadency mark,
canary, canaryyellow,
canton, chaplet, charge, chevron, chief, citron, citronyellow, coat of
arms, cockatrice,
coronet, cream, creamy, crescent, crest, cross, cross moline, crown, device, difference, differencing, eagle, ecru, ermine, ermines, erminites, erminois, escutcheon, falcon, fallow, fallowness, fess, fess point, field, file, flanch, flaxen, fleurdelis, fret, fur, fusil, garland, gilded, gilt, gold, goldcolored, golden, griffin, gules, gyron, hatchment, helmet, heraldic device, honor
point, impalement,
impaling, inescutcheon, label, lemon, lemonyellow, lion, lozenge, luteolous, lutescent, mantling, marshaling, martlet, mascle, metal, motto, mullet, nombril point, ocherish, ocherous, ochery, ochreous, ochroid, ochrous, ochry, octofoil, ordinary, orle, pale, paly, pean, pheon, primrose, primrosecolored,
primroseyellow, purpure, quarter, quartering, rose, sable, saffron, saffroncolored,
saffronyellow, sallow,
saltire, sandcolored,
sandy, scutcheon, shield, spread eagle, straw, strawcolored, subordinary, tenne, tincture, torse, tressure, unicorn, vair, vert, wreath, xanthic, xanthous, yale, yellow, yellowish, yellowishness, yellowness