one
The number 1
The number that comes before two and after zero.
- There is only one apple left on the table.
- She has one brother and two sisters.
- One of my friends is from Spain.
- I have one pen.
- There is one cat in the garden.
- One boy is playing in the park.
A single person or thing
Used instead of repeating a noun to mean a single person or thing.
[something] is the one that [verb]
- This is the one I told you about.
- Which one do you prefer?
- He is the one who helped me.
- This is the one I like.
- Which one is your bag?
- He is the one with a red hat.
A single unit or item
A single person or thing.
- One of the chairs is broken.
- She is one of my best friends.
- This book is a good one.
- One of my shoes is lost.
- He is one of my teachers.
- This is a good one.
United or whole as a single entity
Together as a single group or thing.
[group] is one in [purpose/goal]
- We must act as one to succeed.
- They spoke with one voice on the matter.
- The two companies became one after the merger.
- We work as one team.
- They speak as one group.
- We are one family.
An unspecified person (formal)
'One' means 'any person' in general statements, used in formal English.
One [verb] when [condition]
- One should always tell the truth.
- If one is careful, mistakes can be avoided.
- One must be prepared for change.
- One should eat healthy food.
- One must be polite to others.
- One can learn from mistakes.
- Base: one
- Base: one
- Plural: ones
all in one
1Combined into a single thing
When different things are together in the same product or place.
- It's an all-in-one printer, scanner, and copier.
- She’s an athlete, artist, and scholar all in one.
at one with
1In complete harmony with something/someone
Feeling completely connected and peaceful with something or someone.
- He felt at one with nature.
- She was at one with her surroundings.
for one thing
1Giving a reason among others
Used to introduce one reason when there are more reasons too.
- I can’t go, for one thing I have no money.
- For one thing, it’s too far away.
one by one
1Separately, in sequence
Doing things to each person or thing separately, in order.
- The teacher called the students one by one.
- They entered the room one by one.
one of a kind
1Unique and special
Very special and different from all others.
- Her dress was truly one of a kind.
- Her handmade wedding dress was one of a kind.
- This opportunity is one of a kind.
- He’s one of a kind—no one else has his sense of humor.
one of a kind
2completely unique person or thing
Someone or something that is special and different from all others.
- Her artwork is truly one of a kind.
- He’s one of a kind—there’s no one else like him.