or else

WordReference Random House Learner's Dictionary of American English © 2025

else /ɛls/   adj. [after words like who, what, when, how, etc. in questions;
after pronouns like someone, anything, no one, much, etc.]

1. other than those persons or things mentioned:
   What else could I do? I would have eaten anything else.
2. in addition to persons or things mentioned: Who else was there?
3. other (used in the possessive after a pronoun and before the noun that is possessed):
   someone else's money.

adv. 

4. if not:
   [or + ~] Watch your step, or else you'll slip.
5. otherwise:
   How else could I have acted?

Idioms

6. Idioms or else, or suffer the consequences:
   Do exactly what I say, or else.

WordReference Random House Learner's Dictionary of American English © 2025

or¹ /ɔr; unstressed ɚ/   conj. 

1. (used to connect words, phrases, or clauses that represent or stand for choices, alternatives, or options):
   to be or not to be; Do you want vanilla or chocolate?
2. (used to connect different words or names that refer to the same thing):
   the Hawaiian, or Sandwich, Islands.
3. (used with the word either to connect two clauses showing one choice followed by another):
   Either we go now or we wait till tomorrow.
4. (used to correct or rephrase what was previously said):
   His autobiography, or rather his memoirs, will be published soon.
5. otherwise;
   or else:
   Be here on time, or we'll leave without you.

OR,  an abbreviation of:

1. operating room.
2. Oregon.

-or,² suffix. 

1. -or is used to form nouns that are agents, or that do or perform a function:
   debtor;
   traitor;
   projector;
   repressor;
   sensor;
   tractor.

WordReference Random House Unabridged Dictionary of American English © 2025

else  (els), adj. 

1. other than the persons or things mentioned or implied:
   What else could I have done?
2. in addition to the persons or things mentioned or implied:
   Who else was there?
3. other or in addition (used in the possessive following an indefinite pronoun):
   someone else's money.

adv. 

4. if not (usually prec. by or):
   It's a macaw, or else I don't know birds.
5. in some other way;
   otherwise:
   How else could I have acted?
6. at some other place or time:
   Where else might I find this book?
7. Idioms or else, or suffer the consequences:
   Do what I say, or else.

• bef. 1000; Middle English, Old English elles (cognate with Old High German elles), equivalent. to ell- other (cognate with Gothic aljis, Latin alius, Old Irish aile Greek állos, Armenian ayl other; compare eldritch) + -es -s¹

Usage

The possessive forms of somebody else, everybody else, etc., are somebody else's, everybody else's, the forms somebody's else, everybody's else being considered nonstandard in present-day English. One exception is the possessive for who else, which is occasionally formed as whose else when a noun does not immediately follow:
Is this book yours? Whose else could it be? No, it's somebody else's.

WordReference Random House Unabridged Dictionary of American English © 2025

or¹  (ôr; unstressed ər), conj. 

1. (used to connect words, phrases, or clauses representing alternatives):
   books or magazines; 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 … or;
   or … or;
   whether … or.
4. (used to correct or rephrase what was previously said):
   His autobiography, or rather memoirs, will soon be ready for publication.
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, origin, originally the second, unstressed member of correlative other … or, earlier other … other, Old English āther … oththe, ā-hwæther … oththe, for oththe … oththe either … or; compare ay¹, whether

Usage

See and/or, either. 

or²  (ôr), prep., conj. [Chiefly Irish, Scot., and Eng.]

1. British Terms, Scottish Terms before;
   ere.

• bef. 950; Middle English, Old English ār soon, early; cognate with Old Norse ār, Gothic air early; compare Old English ǣr soon, before, ere

or³  (ôr), [Heraldry.]
n. 

1. Heraldry the tincture, or metal, gold: represented either by gold or by yellow.

adj. 
2. Heraldry of the tincture, or metal, gold:
   a lion or.
• Latin aurum gold
• Middle French
• late Middle English 1400–50

OR  (ôr), n. 

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

OR, 

1. Law on (one's own) recognizance.
2. operating room.
3. operations research.
4. Oregon (approved esp. for use with zip code).
5. owner's risk.

-or¹ :

1. Pronouns a suffix occurring in loanwords from Latin, directly or through Anglo-French, usually denoting a condition or property of things or persons, sometimes corresponding to qualitative adjectives ending in -id ⁴ (ardor;
   honor;
   horror;
   liquor;
   pallor;
   squalor;
   torpor;
   tremor);
   a few other words that originally ended in different suffixes have been assimilated to this group (behavior;
   demeanor;
   glamour).

• Latin -ōr-, stem of -or, earlier -os
• Anglo-French, Old French
• Latin; in some cases continuing Middle English -our

Usage

While the -or spelling of the suffix -or ¹ is characteristic of American English, there are occasional exceptions, as in advertising copy, where spellings such as colour and favour seek to suggest the allure and exclusiveness of a product. The spelling glamour is somewhat more common than glamor--not actually an instance of -or ¹,but conformed to it orthographically in the course of the word's history. In British English -our is still the spelling in most widespread use, -or being commonly retained when certain suffixes are added, as in color ation, honor ary, honor ific, labor ious, odor iferous. The English of the Southern Hemisphere (Australia, New Zealand, South Africa) tends to mirror British practice, whereas Canadian English shares with the U.S. a preference for -or but with -our spellings as freely used variants.
The suffix -or ² is now spelled -or in all forms of English, with the exception of the word savior, often spelled saviour in the U.S. as well as in Britain, esp. with reference to Jesus.

-or² :

1. a suffix forming animate or inanimate agent nouns, occurring originally in loanwords from Anglo-French (debtor;
   lessor;
   tailor;
   traitor);
   it now functions in English as an orthographic variant of -er ¹, usually joined to bases of Latin origin, in imitation of borrowed Latin words containing the suffix -tor (and its alternant -sor). The association with Latinate vocabulary may impart a learned look to the resultant formations, which often denote machines or other less tangible entities which behave in an agentlike way:
   descriptor;
   projector;
   repressor;
   sensor;
   tractor.

• Latin -ātōr- -ator; compare -eur
• Latin -ōr-, stem of -or, extracted from -tōr -tor by construing the t as the ending of the past participle (hence Latin factor maker, equivalent. to fac(ere) to make + -tor, was analyzed as fact(us), past participle of facere + -or); merged with Anglo-French, Old French -ëo(u)r
• Anglo-French, Old French -o(u)r
• Middle English

O.R., 

1. owner's risk.

Collins Concise English Dictionary © HarperCollins Publishers::

else / ɛls/ determiner (postpositive; used after an indefinite pronoun or an interrogative)

1. in addition; more: there is nobody else here
2. other; different: where else could he be?

adverb

1. or else ⇒ if not, then: go away or else I won't finish my work today
2. or something terrible will result: used as a threat: sit down, or else!

Etymology: Old English elles, genitive of el- strange, foreign; related to Old High German eli- other, Gothic alja, Latin alius, Greek allos

Collins Concise English Dictionary © HarperCollins Publishers::

or / ɔː (unstressed) ə/ conjunction (coordinating)

1. used to join alternatives
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
5. or else ⇒
   See else3
6. a poetic word for either or whether as the first element in correlatives, with or also preceding the second alternative

Etymology: 13th Century: contraction of other, used to introduce an alternative, changed (through influence of either) from Old English oththe; compare Old High German odar (German oder)

or / ɔː/ adjective

1. (usually postpositive) of the metal gold

Etymology: 16th Century: via French from Latin aurum gold