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-or 1

One that performs a specified action: accelerator.

[Middle English -or, -our, from Old French -eor, -eur and Anglo-Norman -our, -ur, all from Latin -or, -ōr-.]

-or 2

State; quality; activity: valor.

[Middle English -our, from Old French -eur, from Latin -or, -ōr-.]
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.


suffix forming nouns
a person or thing that does what is expressed by the verb: actor; conductor; generator; sailor.
[via Old French -eur, -eor, from Latin -or or -ātor]


suffix forming nouns
1. indicating state, condition, or activity: terror; error.
2. the US spelling of -our
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 < Anglo-French, Old French -o(u)r < Latin -ōr; compare -eur]
usage: See -or1.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.