# nine

/ˈnaɪn/ (US) · /nˈaɪn/ (UK)

Source: https://englishreference.com/word/nine
Updated: 2026-08-15

## Senses

### 1. the number 9

numeral · CEFR A1

the number 9, which comes after eight and before ten.

For teachers: the cardinal number between eight and ten.

- There are nine students in the advanced photography class this semester.
- The project was divided into nine distinct phases, each requiring a separate budget approval from the board of directors.

### 2. the digit or figure

noun · CEFR A2

the written symbol or figure 9.

For teachers: the graphic symbol or digit representing the number nine.

- The house number was a large brass nine fixed to the gate.
- The accountant noticed that the nine in the final column had been smudged, making the total difficult to verify.

### 3. reliability/purity

noun · CEFR C1 · Technical

a way to measure how reliable a computer system is, using the number of nines in a percentage.

For teachers: a statistical unit of proportion used to express high levels of reliability or purity, such as 'five nines' for 99.999%.

- The company promises four nines of reliability for its cloud storage service.
- Achieving five nines of uptime requires significant investment in redundant hardware and automated failover protocols.

Usage: Usually used in the plural to refer to the number of decimal places in a percentage.

### 4. a baseball team

noun · CEFR B2 · American English · Informal

a name for a baseball team, because there are nine players on the field.

For teachers: a metonymic reference to a baseball team or its starting lineup.

- The local nine won the championship game in the final inning.
- The manager struggled to assemble a competitive nine after three of his star players were sidelined by injuries.

### 5. a weapon

noun · CEFR C1 · Slang

a type of handgun that uses nine-millimeter bullets.

For teachers: a nine-millimeter semi-automatic pistol.

- The detective carried a nine in a holster under his jacket.
- Ballistics experts confirmed that the rounds were fired from a standard nine found at the scene.

## Examples

- I have nine apples in my basket.
- The meeting starts at nine o'clock sharp, so please ensure you arrive a few minutes early.
- The system architecture relies on a nine-layer security protocol designed to prevent unauthorized access at every stage of the data transfer process.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.