fifty

IPA/ˈfɪf.ti/

KK[fˈɪfti]IPA/ˈfɪf.ti/

1.numberA1

Definition

the number that comes after forty-nine and before fifty-one, written in digits as 50

Example

There are fifty chairs in the hall for the guests.

Vikram saved fifty dollars from his part-time job this month.

fifty + noun (money)

Common collocations

fifty dollars
fifty people
fifty miles
fifty percent
fifty years old

Synonyms

half a hundred
formal or literary; uncommon in everyday speech

Grammar Patterns

fifty + noun (plural)

Common Mistakes

She is fifteen years old, not fifteen.' (confusing digits).

She is fifty years old, not fifteen.

the numbers 15 and 50 sound similar; pause clearly on the first syllable ('fif-teen' vs 'fif-ty').

1.nounA1

Definition

the cardinal number made up of five groups of ten, used as a mathematical value or concept

Example

Fifty is half of one hundred, so it is a round number.

fifty as subject of 'is' (singular verb)

In the math test, Yuki had to write fifty as a Roman numeral.

Common collocations

half of fifty
fifty plus …
the number fifty
fifty times

Synonyms

half a hundred
old-fashioned or literary; not used in ordinary speech

Grammar Patterns

fifty + verb (singular)

the number fifty

Usage Note

This sense is used when 'fifty' is the subject or object of a verb (e.g. 'Fifty is…', 'add…to get fifty'), rather than a determiner before a noun ('fifty chairs').

2.nounA2

Definition

the numbers from fifty to fifty-nine, used when talking about a person's age, a temperature, a year in the 1950s, or a speed within that range

Example

Amira is in her early fifties but still runs every morning.

in one's early fifties (age range)

The temperature hit the low fifties at night, so we needed jackets.

the low fifties (temperature range)

Common collocations

in one's fifties
the fifties
the low fifties
the mid fifties
the upper fifties

Grammar Patterns

in one's fifties

the fifties (decade)

the low/mid/upper fifties

Usage Note

Use 'the fifties' to refer to the decade 1950–1959. Use 'in one's fifties' to refer to a person aged 50–59. 'The low fifties' means 50–53; 'the mid fifties' means 54–56; 'the upper fifties' means 57–59.

Common Mistakes

She is in the fifties.' (ambiguous: could mean the decade).

She is in her fifties.

adding 'her' makes it clear you are talking about age, not the 1950s.

3.nounB1

Definition

a piece of paper money worth fifty dollars, especially the US banknote with a face value of fifty dollars

Example

Eve paid for the dinner with a fifty, and the cashier gave her change.

a fifty (short form for a fifty-dollar bill)

The ATM only dispensed fifties, so Gabriela had to break one at the store.

Common collocations

a fifty
a fifty-dollar bill
break a fifty
pay with a fifty
fifties (plural, multiple bills)

Synonyms

fifty-dollar note
used in Australia, New Zealand, and Canada; less common in the US
fifty-dollar bill
full form; more formal than 'a fifty'

Grammar Patterns

a fifty

a fifty-dollar bill

Usage Note

In American English, 'a fifty' is a common shortened form of 'a fifty-dollar bill'. This usage is less common in countries that do not use a 50-dollar denomination.

Common Mistakes

I need to break this fifty-dollar.' (missing 'bill').

I need to break this fifty-dollar bill.

'fifty-dollar' is an adjective and needs a noun like 'bill' after it.

Word family

fifties
nounA2
fiftieth
adjectiveB1
fiftieth
nounB1
fifty-fifty
adverbB1

Synonym discussion

Sense: number/1

'Fifty' is the standard, neutral word for the number 50 in all contexts — counting, money, age, and measurement. 'Half a hundred' is a formal or literary alternative that appears in older texts or poetic language but feels unnatural in everyday conversation. 'The big five-oh' is a humorous, informal expression used mainly for someone turning 50 years old. For example, a friend might say 'Dad is hitting the big five-oh this year,' but you would never use it for a temperature or a price. Use 'fifty' in all ordinary situations; reserve the alternatives for specific registers or occasions.

fifty ↗half a hundredthe big five-oh

Common collocations

Nouns

fifty dollars
fifty years
fifty people
fifty percent
fifty miles
fifty degrees

Adverbs

about fifty
around fifty
nearly fifty
almost fifty
over fifty
under fifty

Phrases

fifty-fifty
fifty something
fifty cents
the dashing fifties

Prepositions

by fifty
at fifty
in one's fifties
over fifty
under fifty

Etymology

Old EnglishProto-GermanicEnglish

'Fifty' comes from Old English 'fīftig', which is a combination of 'fīf' (five) and '-tig' (a suffix meaning 'group of ten', related to 'ten'). The word has been used since before the 12th century to mean 'five tens'. Over time, the pronunciation shifted from the Old English form to the modern English 'fifty'.

First known use

12th century

12th century, in the meaning defined at sense 1

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fifty

fifty — number

1. the number that comes after forty-nine and before fifty-one, written in digits a

Grammar Patterns

Common Mistakes

fifty — noun

1. the cardinal number made up of five groups of ten, used as a mathematical value

Grammar Patterns

Usage Note

2. the numbers from fifty to fifty-nine, used when talking about a person's age, a

Grammar Patterns

Usage Note

Common Mistakes

3. a piece of paper money worth fifty dollars, especially the US banknote with a fa

Grammar Patterns

Usage Note

Common Mistakes

Word family

Synonym discussion

Common collocations

Nouns

Adverbs

Phrases

Prepositions

Etymology

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