# annum

/ˈænəm/ (US) · CEFR C1 · Noun

Source: https://englishreference.com/word/annum
Updated: 2026-05-07

## Definition

a word for one year. It is mostly used in business or science to talk about how much something costs or happens every year.

For teachers: a period of one year. Typically used in formal financial or scientific contexts to specify a rate or frequency per year.

## Examples

- The interest rate is five percent per annum.
- The contract states that the employee will receive twenty-five days of paid leave per annum.
- In astronomical terms, the orbital period of the planet is measured per annum, reflecting its journey around the star relative to Earth's calendar year.

## Pitfalls

- Not "The salary is 50,000 per annumly" but "The salary is 50,000 per annum" — Learners often confuse the noun 'annum' with the adverb 'annually'; 'per' must be followed by the noun.

## Usage notes

- Almost exclusively used in the Latin phrase 'per annum' to mean 'each year' or 'annually'.

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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.