# oh dark hundred

idiom

Source: https://englishreference.com/idiom/oh-dark-hundred
Updated: 2026-08-10

## Meaning

Some unspecified hour in the early morning (implies an unpleasant time to be awake)

## Examples

- I have to wake up at oh dark hundred for work.
- The baby usually wakes up at oh dark hundred.
- Do you really enjoy gym sessions at oh dark hundred?
- The alarm went off at oh dark hundred, and I struggled to get out of my warm bed.
- We had to leave for the airport at oh dark hundred to catch the first flight of the day.
- My neighbor starts his noisy truck at oh dark hundred every morning before the sun comes up.
- The fishing boat left the harbor at oh dark hundred so the crew could reach the best spots before the other boats arrived.
- The soldiers were ordered to begin their march at oh dark hundred, long before the sun had even considered rising over the horizon.

## Origin

Derived from military timekeeping, in which the hours before 10:00 am are prefixed with a zero and read as "oh". The final two digits of the hour, representing zero minutes, are read as "hundred", as in the standard military pronunciation of 0500 as "oh five-hundred". The idiom applies this formal structure to denote an hour that is perceived as unnecessarily early.

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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.