/wun/ , adj.
1. 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.
2. being a person, thing, or individual instance or member of a number, kind, group, or category indicated: one member of the party.
3. existing, acting, or considered as a single unit, entity, or individual.
4. of the same or having a single kind, nature, or condition: We belong to one team; We are of one resolve.
5. noting some indefinite day or time in the future: You will see him one day.
6. a certain (often used in naming a person otherwise unknown or undescribed): One John Smith was chosen.
7. being a particular, unique, or only individual, item, or unit: I'm looking for the one adviser I can trust.
8. noting some indefinite day or time in the past: We all had dinner together one evening last week.
9. of no consequence as to the character, outcome, etc.; the same: It's all one to me whether they go or not.
10. the first and lowest whole number, being a cardinal number; unity.
11. a symbol of this number, as 1 or I.
12. a single person or thing: If only problems would come one at a time!
13. a die face or a domino face having one pip.
14. a one-dollar bill: to change a five-dollar bill for five ones.
15. ( cap. ) 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.
16. at one ,
a. in a state of agreement; of one opinion.
b. united in thought or feeling; attuned: He felt at one with his Creator.
17. one and all , everyone: They came, one and all, to welcome him home.
18. one by one , singly and successively: One by one the children married and moved away.
19. one for the road . See road (def. 8).
20. a person or thing of a number or kind indicated or understood: one of the Elizabethan poets.
21. (in certain pronominal combinations) a person unless definitely specified otherwise: every one.
22. (with a defining clause or other qualifying words) a person or a personified being or agency: the evil one; the one I love.
23. any person indefinitely; anyone: as good as one would desire.
24. Chiefly Brit. (used as a substitute for the pronoun I): Mother had been ailing for many months, and one should have realized it.
25. a person of the speaker's kind; such as the speaker himself or herself: to press one's own claims.
26. something or someone of the kind just mentioned: The portraits are fine ones. Your teachers this semester seem to be good ones.
27. something available or referred to, esp. in the immediate area: Here, take one - they're delicious. The bar is open, so have one on me!
[ bef. 900; ME oon, OE an; c. D een, G ein, Goth ains, L unus (OL oinos ); akin to Gk oíne ace on a die ]
Usage . 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 he 1 , they .