English

Alternative forms

• Arabic numerals: 1
• Roman numerals: I
• Exponential notation: 10⁰

Etymology

Numeral

1. 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.

   There is only one Earth.

   In Western culture, a baby turns one year old a year after its birth.

   One person, one vote.

2. The ordinality of an element which has no predecessor, usually called first or number one.

Pronoun

1. one thing (among a group of others); one member of a group

   The big one looks good.

   I want the green one.

2. any person (applying to people in general)

   One shouldn’t be too quick to judge.

   One’s guilt may trouble one, but it is best to not let oneself be troubled by things which cannot be changed.

Noun

1. The neutral element with respect to multiplication in a ring.
2. The digit or figure 1.
3. A one-dollar bill.
4. One run scored by hitting the ball and running between the wickets; a single.

Adjective

1. 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.

2. Being a single, unspecified thing; a; any.

   My aunt used to say, "One day is just like the other."

3. Sole, only.

   He is the one man who can help you.

4. Whole, entire.

   Body and soul are not separate; they are one.

5. In agreement.

   We are one on the importance of learning.

6. The same.

   The two types look very different, but are one species.

7. Being a preeminent example.

   He is one hell of a guy.

8. Being an unknown person with the specified name.

   The town records from 1843 showed the overnight incarceration of one "A. Lincoln".