# ides

/ˈaɪdz/ (UK) · CEFR C2 · Noun

Source: https://englishreference.com/word/ides
Updated: 2026-10-16

## Definition

the middle day of a month in the old Roman calendar. You see it today almost only in the phrase for March 15, a famous date in Roman history.

For teachers: the middle day of a month in the ancient Roman calendar, falling on the 15th in long months and the 13th in short months. Survives in modern English chiefly in the fixed phrase for March 15.

## Examples

- The ides mark the middle of the month.
- In the old calendar, the ides of the third month fall on the fifteenth day.
- While modern readers link the ides with bad luck, people in old times treated them as a routine date for settling debts.

## Usage notes

- Plural in form and takes a plural verb; almost always appears as 'the ides of' plus a month.

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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.