# day

/ˈdeɪ/ (US) · /dˈeɪ/ (UK)

Source: https://englishreference.com/word/day
Updated: 2026-06-19

## Senses

### 1. 24-hour period

noun · CEFR A1

a period of 24 hours, usually starting from midnight.

For teachers: a standard unit of time representing one full rotation of the Earth, conventionally measured from midnight to midnight.

- There are seven days in a week and 365 days in a year.
- The contract stipulates that the goods must be delivered within ten working days of the initial purchase order.

### 2. daylight hours

noun · CEFR A1

the time between when the sun rises and when it sets.

For teachers: the period of light between dawn and nightfall; the diurnal portion of the 24-hour cycle.

- The days are much longer in the summer than in the winter.
- As the winter solstice approached, the days grew noticeably shorter, leaving the villagers with only a few hours of usable light.

### 3. work or school hours

noun · CEFR A2

the part of the day that you spend at your job or at school.

For teachers: the portion of a day dedicated to a specific activity, typically professional labor or education.

- I had a very busy day at the office and I am tired now.
- After a grueling day on the assembly line, the workers were eager to return home and rest before the next shift began.

### 4. a specific era

noun · CEFR B1

a particular time in history or in someone's life.

For teachers: a specific period or era, often characterized by the prominence of a person, movement, or technology.

- In my grandfather's day, people didn't have mobile phones.
- The historian argued that the glory days of the empire were already fading by the time the new emperor took the throne.

### 5. planetary rotation

noun · CEFR B2 · Technical

the time it takes for a planet to turn around once.

For teachers: the duration of one complete rotation of a celestial body on its axis.

- A day on Mars is slightly longer than a day on Earth.
- Venus is unique in our solar system because its sidereal day is actually longer than its orbital year.

## Examples

- I work five days a week.
- The shortest day of the year occurs in December for people living in the northern hemisphere.
- While a solar day lasts exactly twenty-four hours, a sidereal day is slightly shorter because it measures Earth's rotation relative to the distant stars rather than the sun.

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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.