Nearby words

  1. ondes martenot,
  2. ondine,
  3. onding,
  4. ondo,
  5. ondograph,
  6. one and all,
  7. one and only,
  8. one and the same,
  9. one another,
  10. one by one


Origin of one

before 900; Middle English oon, Old English ān; cognate with Dutch een, German ein, Gothic ains, Latin ūnus (OL oinos); akin to Greek oínē ace on a die

Can be confusedone wan won (see usage note at the current entry)

Usage note

One as an indefinite pronoun meaning “any person indefinitely, anyone” is more formal than you, which is also used as an indefinite pronoun with the same sense: One (or you ) should avoid misconceptions. One (or you ) can correct this fault in three ways. When the construction requires that the pronoun be repeated, either one or he or he or she is used; he or he or she is the more common in the United States: Wherever one looks, he (or he or she ) finds evidence of pollution. In speech or informal writing, a form of they sometimes occurs: Can one read this without having their emotions stirred?
In constructions of the type one of those who (or that or which ), the antecedent of who is considered to be the plural noun or pronoun, correctly followed by a plural verb: He is one of those people who work for the government. Yet the feeling that one is the antecedent is so strong that a singular verb is commonly found in all types of writing: one of those people who works for the government. When one is preceded by only in such a construction, the singular verb is always used: the only one of her sons who visits her in the hospital.
The substitution of one for I, a typically British use, is usually regarded as an affectation in the United States. See also he1, they. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for at one



  1. single; lone; not two or moreone car
  2. (as pronoun)one is enough for now; one at a time
  3. (in combination)one-eyed; one-legged
  1. distinct from all others; only; uniqueone girl in a million
  2. (as pronoun)one of a kind
  1. a specified (person, item, etc) as distinct from another or others of its kindraise one hand and then the other
  2. (as pronoun)which one is correct?
a certain, indefinite, or unspecified (time); someone day you'll be sorry
informal an emphatic word for a 1, an 1 it was one hell of a fight
a certain (person)one Miss Jones was named
in one or all in one combined; united
all one
  1. all the same
  2. of no consequenceit's all one to me
at one (often foll by with) in a state of agreement or harmony
be made one (of a man and a woman) to become married
many a one many people
neither one thing nor the other indefinite, undecided, or mixed
never a one none
one and all everyone, without exception
one by one one at a time; individually
one or two a few
one way and another on balance
off on one informal exhibiting bad temper; ranting
one with another on average


an indefinite person regarded as typical of every personone can't say any more than that
any indefinite person: used as the subject of a sentence to form an alternative grammatical construction to that of the passive voiceone can catch fine trout in this stream
archaic an unspecified personone came to him


the smallest whole number and the first cardinal number; unitySee also number (def. 1)
a numeral (1, I, i, etc) representing this number
informal a joke or story (esp in the one about)
music the numeral 1 used as the lower figure in a time signature to indicate that the beat is measured in semibreves
something representing, represented by, or consisting of one unit
Also called: one o'clock one hour after noon or midnight
a blow or setback (esp in the phrase one in the eye for)
the one (in Neo-Platonic philosophy) the ultimate being
the Holy One or the One above God
the Evil One Satan; the devil
Related formsRelated prefixes: mono-, uni-Related adjective: single

Word Origin for one

Old English ān, related to Old French ān, ēn, Old High German ein, Old Norse einn, Latin unus, Greek oinē ace

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

Word Origin and History for at one


Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with at one

at one

In agreement, in harmony, as in John and Pat were at one on every subject except her cat, which made him sneeze, or Springtime always makes me feel at one with nature. [1300s]


In addition to the idioms beginning with one

  • one and all
  • one and only
  • one and the same
  • one another
  • one by one
  • one eye on
  • one fell swoop, in
  • one foot in the grave, have
  • one for the books
  • one for the road
  • one good turn deserves another
  • one in a million
  • one jump ahead
  • one man's meat is another man's poison
  • one of a kind
  • one of these days
  • one of those days
  • one on one
  • one on, that's
  • one picture is worth a thousand words
  • one up
  • one way or another

also see:

  • all in one piece
  • all the same (one)
  • A-1 (A-one)
  • as one
  • at one
  • at one stroke
  • at one time
  • at one time or another
  • back to the drawing board (square one)
  • each and every (last one)
  • each other (one another)
  • fast one
  • for one, 1
  • go one better
  • hang (one) on
  • harp on (one string)
  • hole in one
  • in one ear and out the other
  • in the same (in one) breath
  • irons in the fire, more than one
  • it takes one to know one
  • just one of those things
  • look out for (number one)
  • more than one way to skin a cat
  • not one iota
  • number one
  • on the one hand
  • (one) picture is worth a thousand words
  • put all one's eggs in one basket
  • quick one
  • seen one, seen them all
  • six of one, half dozen of the other
  • that's one on me
  • tie one on
  • wear another (more than one) hat
  • with one arm tied behind one's back
  • with one voice
  • words of one syllable

(Note that this listing does not include those idioms where one is a personal pronoun meaning “someone” or “oneself.”)

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.