An hour is a period of sixty minutes. It also refers to a specific time of day, a scheduled period of activity or work, or a significant moment: She dedicates one hour every evening to practising her English writing skills.
What Does Hour Mean?
Hour comes from Old French hore, derived from Latin hora, which itself came from Ancient Greek hōra (ὥρα), meaning "season, period of time". The Romans divided the day into twelve equal parts called horae. The word has been in English since the 13th century, arriving via the Norman French spoken after the Conquest of 1066. Note that the H is completely silent — hour sounds like our — which is why we use the article an before it, not a.
In modern English, hour covers three overlapping senses: (1) a unit of duration equal to sixty minutes; (2) the time shown on a clock at a particular point in the day ("on the hour", "at what hour?"); and (3) a broader period associated with a particular activity or significance ("office hours", "her darkest hour"). Understanding which sense is intended usually depends on context.
Note that when hour works as a modifier before a noun, it remains singular and takes a hyphen: a two-hour delay, not a two-hours delay. This rule applies to all time-unit modifiers in English.
Example Sentences
| Sentence | CEFR level & note |
|---|---|
| The lesson lasts one hour. | A2 — simple present, basic duration |
| She dedicates one hour every evening to practising her English writing skills. | B1 — frequency adverbial, gerund complement |
| We arrived half an hour before the doors opened. | B1 — fractional time expression, time clause |
| The rescue team worked for over eighteen hours without a break before the survivors were found. | B2 — extended time phrase, passive construction |
| Historians regard that speech as Churchill's finest hour, a moment that defined not only the man but the nation he led. | C1 — idiomatic use, appositive clause, formal register |
Collocations
| Collocation | Meaning & example |
|---|---|
| rush hour | The busy period when most people travel to or from work. The roads are terrible during rush hour. |
| office hours | The times during which an office or institution is open. Please call during office hours. |
| opening hours | The times a shop or venue is open to the public. Check the opening hours on the website. |
| working hours | The hours during which someone works. My working hours are nine to five. |
| per hour | For each hour; used for speed or rates. The train travels at 200 kilometres per hour. |
| an hour ago | Sixty minutes in the past. He left an hour ago. |
| within the hour | In less than sixty minutes from now. Your order will arrive within the hour. |
| small hours | The hours just after midnight. They talked into the small hours of the morning. |
| on the hour | Exactly at a full clock hour. The bus departs on the hour, every hour. |
| finest hour | A person's or group's greatest moment of achievement. The rescue operation was the team's finest hour. |
Usage Notes
Key points for learners
Silent H, so use "an": Because the H is silent, hour starts with the vowel sound /aʊ/. Always write an hour, an hourly report, an hour's walk — never a hour.
Modifier rule: When hour modifies a noun, keep it singular and add a hyphen: a two-hour meeting, a three-hour film, a 24-hour service. The plural hours is only used as the main noun: The meeting lasted two hours.
Possessive constructions: Both an hour's delay and a delay of one hour are correct. The possessive with 's is more concise and natural in spoken and informal written English.
Telling the time: In British English, half past (2:30), quarter past (2:15), and quarter to (2:45) are all preferred over the American two-thirty, two-fifteen, and two forty-five in informal speech, though the digital style is increasingly common.
Common Mistakes
Watch Out For
I waited a hour for the bus.
I waited an hour for the bus. (silent H — use "an" before a vowel sound)
It was a two-hours journey.
It was a two-hour journey. (hour stays singular as a hyphenated modifier)
The meeting is in one hours time.
The meeting is in one hour's time. (possessive apostrophe required)
She works in the office hours.
She works during office hours. (no article with this fixed collocation; use "during")