WordReference Random House Learner's Dictionary of American English © 2015
one /wʌn/USA pronunciation
adj. [before a noun]
being or amounting to a single unit or individual or entire thing;
equal to the number 1:one child; only one piece of cake left.
being an individual instance, example, or member of a number, kind, or group indicated:one member of the team.
of the same or having a single kind, nature, or condition:We are of one mind.
(used to refer to an unspecified or imprecise day or time):one evening last week.
[before a proper noun or name] (used to name a person otherwise unknown or not yet described):One John Smith was chosen.
[before a singular countable noun] being a particular or only individual, item, or unit:She's the one person I can trust.
(used to show strong feeling about the noun or adjective that follows) a or an:That is one smart dog.
the first and lowest whole number, being a cardinal number; a unit:Ten minus nine leaves one.
a symbol of this number, as 1 or I.
a single person or thing:Let's do one at a time.
a one-dollar bill.
(used to stand for a person or thing of a number or kind that is about to be indicated):He is one of the Elizabethan poets.
(used to stand for a person or thing that has just been mentioned or indicated, or is already understood from the context):The portraits are good ones.
a person, or a personified being:Satan, the evil one.
any person or thing; people in general:One shouldn't cry over spilled milk (= People in general, including the speaker, shouldn't get upset about things that can't be fixed.)
all one, the same:You can stay or go; it's all one to me. (= It doesn't matter to me which action you take.)
- with complete agreement;
unanimously:They voted as one.
- all at the same time; in unison:We rose to our feet as one.
Idiomsone and all, everyone.
Idiomsone by one, singly and following after another.
- united in thought or feeling;
attuned:to feel at one with the world.
Collins Concise English Dictionary © HarperCollins Publishers::
one /wʌn/ determiner
- single; lone; not two or more
- (as pronoun): one is enough for now, one at a time
- (in combination): one-eyed, one-legged
- distinct from all others; only; unique: one girl in a million
- (as pronoun): one of a kind
- a specified (person, item, etc) as distinct from another or others of its kind: raise one hand and then the other
- (as pronoun): which one is correct?
- a certain, indefinite, or unspecified (time); some: one day you'll be sorry
an emphatic word for a, an1: it was one hell of a fight
- a certain (person): one Miss Jones was named
- in one, all in one ⇒ combined; united
- all one ⇒ all the same
- of no consequence: it's all one to me
- at one ⇒ (often followed 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
- one with another ⇒ on average
- an indefinite person regarded as typical of every person: one 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 voice: one can catch fine trout in this stream
- archaic an unspecified person: one came to him
- the smallest whole number and the first cardinal number; unity
- a numeral (1, I, i, etc) representing this number
- informal a joke or story (esp in the one about)
- 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 Holy One, the One above ⇒ God
- the Evil One ⇒ Satan; the devil
Related prefixes: mono-, uni-Etymology: Old English ān, related to Old French ān, ēn, Old High German ein, Old Norse einn, Latin unus, Greek oinē ace
'one' also found in these entries: