definition of or by The Free Dictionary

OR 1



A logical operator that returns a true value if one or both operands are true.

OR 2


1. operating room

2. operations research

3. Oregon

or 1

 (ôr; ər when unstressed)



a. Used to indicate an alternative, usually only before the last term of a series: hot or cold; this, that, or the other.

b. Used to indicate the second of two alternatives, the first being preceded by either or whether: Your answer is either ingenious or wrong. I didn’t know whether to laugh or cry.

c. Archaic Used to indicate the first of two alternatives, with the force of either or whether.

2. Used to indicate a synonymous or equivalent expression: acrophobia, or fear of great heights.

3. Used to indicate uncertainty or indefiniteness: two or three.

[Middle English, from other, or (from Old English, from oththe) and from outher (from Old English āhwæther, āther; see either).]

Usage Note: When all the elements in a series connected by or are singular, the verb they govern is singular: Tom or Jack is coming. Beer, ale, or wine is included in the charge. When all the elements are plural, the verb is plural. When the elements do not agree in number, some grammarians have suggested that the verb should agree in number with the nearest element: Tom or his sisters are coming. The girls or their brother is coming. Cold symptoms or headache is the usual first sign. Other grammarians, however, have argued that such constructions are inherently illogical and that the only solution is to revise the sentence to avoid the problem of agreement: Either Tom is coming or his sisters are. The usual first sign may be either cold symptoms or a headache. See Usage Notes at and/or, either, neither, nor1.

or 2

 (ôr) Archaic


Before. Followed by ever or ere: “I doubt he will be dead or ere I come” (Shakespeare).

[Middle English, variant of er, from Old English ǣr, soon, early, and from Old Norse ār; see ayer- in Indo-European roots.]

or 3


n. Heraldry

Gold, represented in heraldic engraving by a white field sprinkled with small dots.

[Middle English, from Old French, from Latin aurum.]

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ɔː; unstressed ə)

conj (coordinating)

1. used to join alternatives: apples or pears; apples or pears or cheese; apples, pears, or cheese.

2. used to join rephrasings of the same thing: to serve in the army, or rather to fight in the army; twelve, or a dozen.

3. used to join two alternatives when the first is preceded by either or whether: whether it rains or not we’ll be there; either yes or no.

4. one or two a few

6. a poetic word for either or whether as the first element in correlatives, with or also preceding the second alternative

[C13: contraction of other, used to introduce an alternative, changed (through influence of either) from Old English oththe; compare Old High German odar (German oder)]




(subordinating; foll by ever or ere) before; when

[Old English ār soon; related to Old Norse ār early, Old High German ēr]




(Heraldry) (usually postpositive) heraldry of the metal gold

[C16: via French from Latin aurum gold]


abbreviation for

1. (Economics) operations research

2. (Placename) Oregon

3. (Military) military other ranks

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ɔr; unstressed ər)


1. (used to connect words, phrases, or clauses representing alternatives): to be or not to be.

2. (used to connect alternative terms for the same thing): the Hawaiian, or Sandwich, Islands.

3. (used in correlation): Either we go now or wait till tomorrow.

4. (used to correct or rephrase what was previously said): His autobiography, or rather memoirs, will be published soon.

5. otherwise; or else: Be here on time, or we’ll leave without you.

6. Logic. the connective used in disjunction.

[1150–1200; Middle English; compare ay1, whether]

usage: See and/or, either.



prep., conj. Archaic.

before; ere.

[before 950; Middle English, Old English ār soon]




the heraldic color yellow or gold.

[1400–50; late Middle English < Middle French < Latin aurum gold]



a Boolean operator that returns a positive result when either or both operands are positive.



1. operating room.

2. operations research.

3. Oregon.



a suffix occurring in loanwords from Latin, directly or through Anglo-French, usu. denoting a condition or property of things or persons, sometimes corresponding to qualitative adjectives ending in -id4 (honor; horror; liquor; pallor); a few other words that orig. ended in different suffixes have been assimilated to this group (behavior; demeanor; glamour).

[< Latin; in some cases continuing Middle English -our < Anglo-French, Old French < Latin -ōr-, s. of -or, earlier -os]

usage: The -or spelling of the suffix -or1 is characteristic of American English, with occasional exceptions. In British English -our is still the most common spelling, -or often being retained when certain suffixes are added, as in coloration, honorary, and laborious. The English of Australia, New Zealand, and South Africa tends to mirror British practice, whereas Canadian English is about equally divided between U.S. and British forms.―The suffix -or2 is now spelled -or in all forms of English, except for the word savior, once often spelled saviour in the U.S. as in Britain, esp. with reference to Jesus. But the official spelling of Catholics, Episcopalians, Presbyterians, and Methodists is now savior; saviour is now only British.



a suffix forming animate or inanimate agent nouns, occurring orig. in loanwords from Anglo-French (debtor; tailor; traitor); it now functions in English as an orthographic variant of -er1, usu. joined to bases of Latin origin, in imitation of borrowed Latin words containing the suffix -tor (and alternant -sor). Resultant formations often denote machines or less tangible entities that behave in an agentlike way: projector; repressor; sensor; tractor.
[Middle English -o(u)r -ōr; compare -eur]

Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.


1. basic uses

You use or when you are mentioning two or more alternatives or possibilities. You use or to link words, phrases, or clauses.

Would you like some coffee or tea, Dr Floyd?

It is better to delay planting if the ground is very wet or frosty.

Do you want to go to the beach or spend time at home?

2. used with negative words

You use or instead of ‘and’ after using a negative word. For example, say ‘I do not like coffee or tea’. Don’t say ‘I do not like coffee and tea‘.

The situation is not fair on the children or their parents.

It is not poisonous and will not harm any animals or birds.

The house is not large or glamorous.

3. verb agreement

When you link two or more nouns using or, you use a plural verb after plural countable nouns, and a singular verb after singular countable or uncountable nouns.

Even minor changes or developments were reported in the press.

If your son or daughter is failing at school, it is no use being angry.

4. ‘either … or’

You use either with or when you are mentioning two alternatives and you want to say that no other alternatives are possible. Either goes in front of the first alternative and or goes in front of the second one.

Replace it with a broadband access device, either rented or costing around $500.

After neither, you usually use nor.

He speaks neither English nor German.

5. linking more than two items

When you are linking more than two items, you usually only put or in front of the last one. After each of the others you put a comma. Often the comma is omitted in front of or.

Flights leave from Heathrow, Manchester, Gatwick, or Glasgow.

Students are asked to take another course in English, science or mathematics.

6. beginning a sentence with ‘or’

You don’t normally put or at the beginning of a sentence, but you can sometimes do so when you are reporting what someone says or thinks.

I may go home and have a steak. Or I may have some spaghetti.

7. used for correcting

You can use or when you are correcting a mistake you have made, or when you think of a better way of saying something.

We were considered by the others to be mad, or at least very strange.

Collins COBUILD English Usage © HarperCollins Publishers 1992, 2004, 2011, 2012

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