one
gb/wˈʌn/ us/wˈʌn/
A1
English
~ 200
Senses
0 senses
numeral
A1
quantity
1
The number 1
The number that comes before two and after zero.
Common mistake:
Learners sometimes confuse 'one' with 'a' or 'an'. 'One' emphasizes the exact number, while 'a/an' may not.
Synonyms
single (Often used to emphasize being alone or only one, sometimes with stylistic differences.)
Antonyms
zero (Represents the absence of any quantity, opposite of having one.)
Collocations
one day
|one person
|one thing
|one time
Themes
math
|daily life
|core_vocabulary
|education
Examples
- There is only one apple left on the table.
- She has one brother and two sisters.
- One of my friends is from Spain.
Learner examples
- I have one pen.
- There is one cat in the garden.
- One boy is playing in the park.
pronoun
A2
relation
2
A single person or thing
Used instead of repeating a noun to mean a single person or thing.
Usage pattern:
[something] is the one that [verb]
Common mistake:
Learners sometimes forget to match 'one' with singular verbs and pronouns.
Synonyms
individual (More formal and often refers to a person specifically.)
Antonyms
many (Refers to more than one person or thing.)
Collocations
the one who
|the one that
|this one
|that one
Themes
daily life
|core_vocabulary
|communication
Examples
- This is the one I told you about.
- Which one do you prefer?
- He is the one who helped me.
Learner examples
- This is the one I like.
- Which one is your bag?
- He is the one with a red hat.
Noun
A2
entity
3
A single unit or item
A single person or thing.
Synonyms
single unit (More technical or literal in some contexts.)
Antonyms
multiple (Refers to more than one unit or item.)
Collocations
one of them
|one of us
|one of the best
Themes
daily life
|core_vocabulary
Examples
- One of the chairs is broken.
- She is one of my best friends.
- This book is a good one.
Learner examples
- One of my shoes is lost.
- He is one of my teachers.
- This is a good one.
adjective
B1
property
4
United or whole as a single entity
Together as a single group or thing.
Usage pattern:
[group] is one in [purpose/goal]
Synonyms
united (Emphasizes being joined together for a purpose.)
Antonyms
divided (Separated into parts, lacking unity.)
Collocations
one nation
|act as one
|speak with one voice
Themes
relationships
|core_vocabulary
Examples
- We must act as one to succeed.
- They spoke with one voice on the matter.
- The two companies became one after the merger.
Learner examples
- We work as one team.
- They speak as one group.
- We are one family.
pronoun
formal
B2
relation
5
An unspecified person (formal)
'One' means 'any person' in general statements, used in formal English.
Usage pattern:
One [verb] when [condition]
Common mistake:
Learners often use 'one' in informal contexts where 'you' would sound more natural to native speakers.
Synonyms
you (impersonal) ('You' is less formal and more common in everyday English for general statements.)
Collocations
one should know
|if one wishes
Themes
formal language
|core_vocabulary
|communication
Examples
- One should always tell the truth.
- If one is careful, mistakes can be avoided.
- One must be prepared for change.
Learner examples
- One should eat healthy food.
- One must be polite to others.
- One can learn from mistakes.
Grammar
Dictionary form
one
IPA
GB/wˈʌn/
US/wˈʌn/
Syllables & stress
one (1 syllable)
Stress on 1st syllable (one)
Word forms
Adjective
- Base: one
Noun
- Base: one
- Plural: ones
Word family
Expressions
all in one
1/ˈɔl ˈɪn wˈʌn/
fixed phrase
Combined into a single thing
When different things are together in the same product or place.
Examples
- It's an all-in-one printer, scanner, and copier.
- She’s an athlete, artist, and scholar all in one.
at one with
1/ˈæt wˈʌn wˈɪθ/
fixed phrase
In complete harmony with something/someone
Feeling completely connected and peaceful with something or someone.
Examples
- He felt at one with nature.
- She was at one with her surroundings.
for one thing
1/fɚ wˈʌn θˈɪŋ/
fixed phrase
Giving a reason among others
Used to introduce one reason when there are more reasons too.
Examples
- I can’t go, for one thing I have no money.
- For one thing, it’s too far away.
one by one
1/wˈʌn bˈaɪ wˈʌn/
fixed phrase
Separately, in sequence
Doing things to each person or thing separately, in order.
Examples
- The teacher called the students one by one.
- They entered the room one by one.
one of a kind
1/wˈʌn əv ə kˈaɪnd/
idiom
Unique and special
Very special and different from all others.
Examples
- 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
2/wˈʌn əv ə kˈaɪnd/
idiom
completely unique person or thing
Someone or something that is special and different from all others.
Examples
- Her artwork is truly one of a kind.
- He’s one of a kind—there’s no one else like him.