- The same.
"The two types look very different, but are one species."
- Being a single, unspecified thing; a; any.
"My aunt used to say, "One day is just like the other.""
- In agreement.
"We are one on the importance of learning."
- Being an unknown person with the specified name.
"The town records from 1843 showed the overnight incarceration of one “A. Lincoln”."
- Of a period of time, being particular; as, one morning, one year.
"One day the prince set forth to kill the dragon that had brought terror to his father’s kingdom for centuries."
- Whole, entire.
"Body and soul are not separate; they are one."
- Being a preeminent example.
"He is one hell of a guy."
- Sole, only.
"He is the one man who can help you."
- The digit or figure 1.
- A joke or amusing anecdote.
- (mathematics) The neutral element with respect to multiplication in a ring.
- (cricket) One run scored by hitting the ball and running between the wickets; a single.
- (US) A one-dollar bill.
- (colloquial) A particularly special or compatible person or thing.
- The ordinality of an element which has no predecessor, usually called first or number one.
- (cardinal) A numerical value equal to 1; the first number in the set of natural numbers (especially in number theory); the cardinality of the smallest nonempty set. Ordinal: first.
"One person, one vote."
"In many cultures, a baby turns one year old a year after its birth."
"There is only one God."
- (indefinite personal pronoun) Any person (applying to people in general).
"One’s guilt may trouble one, but it is best not to let oneself be troubled by things which cannot be changed. One shouldn’t be too quick to judge."
- (impersonal pronoun, sometimes with "the") The first mentioned of two things or people, as opposed to the other.
"She offered him an apple and an orange; he took one and left the other."
- (impersonal pronoun) One thing (among a group of others); one member of a group.
"The big one looks good. I want the green one. A good driver is one who drives carefully."
- (pronoun) Any person, entity or thing.
""driver", noun: one who drives."
- (obsolete, transitive) To cause to become one; to gather into a single whole; to unite.