- being or amounting to a single unit or individual or entire thing, item, or object rather than two or more; a single: one woman; one nation; one piece of cake.
- being a person, thing, or individual instance or member of a number, kind, group, or category indicated: one member of the party.
- existing, acting, or considered as a single unit, entity, or individual.
- of the same or having a single kind, nature, or condition: We belong to one team; We are of one resolve.
- noting some indefinite day or time in the future: You will see him one day.
- a certain (often used in naming a person otherwise unknown or undescribed): One John Smith was chosen.
- being a particular, unique, or only individual, item, or unit: I’m looking for the one adviser I can trust.
- noting some indefinite day or time in the past: We all had dinner together one evening last week.
- of no consequence as to the character, outcome, etc.; the same: It’s all one to me whether they go or not.
- the first and lowest whole number, being a cardinal number; unity.
- a symbol of this number, as 1 or I.
- a single person or thing: If only problems would come one at a time!
- a die face or a domino face having one pip.
- a one-dollar bill: to change a five-dollar bill for five ones.
- (initial capital letter) Neoplatonism. the ultimate reality, seen as a central source of being by whose emanations all entities, spiritual and corporeal, have their existence, the corporeal ones containing the fewest of the emanations.
- a person or thing of a number or kind indicated or understood: one of the Elizabethan poets.
- (in certain pronominal combinations) a person unless definitely specified otherwise: every one.
- (with a defining clause or other qualifying words) a person or a personified being or agency: the evil one; the one I love.
- any person indefinitely; anyone: as good as one would desire.
- Chiefly British. (used as a substitute for the pronoun I): Mother had been ailing for many months, and one should have realized it.
- a person of the speaker’s kind; such as the speaker himself or herself: to press one’s own claims.
- something or someone of the kind just mentioned: The portraits are fine ones. Your teachers this semester seem to be good ones.
- something available or referred to, especially in the immediate area: Here, take one—they’re delicious. The bar is open, so have one on me!
- at one,
- in a state of agreement; of one opinion.
- united in thought or feeling; attuned: He felt at one with his Creator.
- one and all, everyone: They came, one and all, to welcome him home.
- one by one, singly and successively: One by one the children married and moved away.
- one for the road. road(def 10).
noun British informal
- a single continuous action (esp in the phrase down it in a oner)
- an outstanding person or thing
- a heavy blow
- single; lone; not two or moreone car
- (as pronoun)one is enough for now; one at a time
- (in combination)one-eyed; one-legged
- distinct from all others; only; uniqueone girl in a million
- (as pronoun)one of a kind
- a specified (person, item, etc) as distinct from another or others of its kindraise one hand and then the other
- (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
- all the same
- 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
n.c.1200, from Old English an (adjective, pronoun, noun) “one,” from Proto-Germanic *ainaz (cf. Old Norse einn, Danish een, Old Frisian an, Dutch een, German ein, Gothic ains), from PIE *oi-no- “one, unique” (cf. Greek oinos “ace (on dice);” Latin unus “one;” Old Persian aivam; Old Church Slavonic -inu, ino-; Lithuanian vienas; Old Irish oin; Breton un “one”). Originally pronounced as it still is in only, and in dialectal good ‘un, young ‘un, etc.; the now-standard pronunciation “wun” began c.14c. in southwest and west England (Tyndale, a Gloucester man, spells it won in his Bible translation), and it began to be general 18c. Use as indefinite pronoun influenced by unrelated French on and Latin homo. One and only “sweetheart” is from 1906. One of those things “unpredictable occurrence” is from 1934. Slang one-arm bandit “a type of slot machine” is recorded by 1938. One-night stand is 1880 in performance sense; 1963 in sexual sense. One of the boys “ordinary amiable fellow” is from 1893. One-track mind is from 1927. Drinking expression one for the road is from 1950 (as a song title). In addition to the idioms beginning with one
(Note that this listing does not include those idioms where one is a personal pronoun meaning “someone” or “oneself.”)