-or

1

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 -id4 (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).

Origin of -or

1
< Latin; in some cases continuing Middle English -our < Anglo-French, Old French < Latin -ōr-, stem of -or, earlier -os

Usage note

While the -or spelling of the suffix -or1 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 -or1 , 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 -or2 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, especially with reference to Jesus.

Definition for -or (2 of 2)

-or

2

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 -er1, 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; plexor; projector; repressor; sensor; tractor.

Origin of -or

2
Middle English < Anglo-French, Old French -o(u)r < 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 < Latin -ātōr- -ator; cf. -eur
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for -or (1 of 2)

-or

1

suffix forming nouns

a person or thing that does what is expressed by the verbactor; conductor; generator; sailor

Word Origin for -or

via Old French -eur, -eor, from Latin -or or -ātor

British Dictionary definitions for -or (2 of 2)

-or

2

suffix forming nouns

indicating state, condition, or activityterror; error
the US spelling of -our
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012