half-hour

IPA/ˌhɑːf ˈaʊə(r)/
KK[hˈæfˌaʊɚ]IPA/ˌhæf ˈaʊər/

half-hour — noun

1. A length of time that lasts 30 minutes.

1.nounA1
Definition

A length of time that lasts 30 minutes.

Example

The train from Taipei arrives in half an hour.

half an hour — common fixed phrase

Christopher waited for half an hour outside the library.

Common collocations
  • half an hour
  • a half hour
  • every half hour
  • within the half-hour
  • half an hour later
Synonyms
  • 30 minutes

    more formal and exact; preferred in schedules and written instructions

  • half an hour

    the most common conversational form in both British and American English

Antonyms
  • hour

    a period twice as long

Grammar Patterns

half an hour

a half hour

every half hour

half an hour + verb

Common Mistakes

I will be back in half hour.
I will be back in half an hour.
The indefinite article 'an' is required before 'hour' in this fixed expression.
The movie lasts for half of hour.
The movie lasts for half an hour.
Use 'half an hour' or 'a half hour', not 'half of hour'.

2. The time exactly 30 minutes past the start of an hour, used when telling when ev

2.nounA2
Definition

The time exactly 30 minutes past the start of an hour, used when telling when events happen rather than how long they last.

Example

The bus comes at the half-hour, so the next one is at half past three.

at the half-hour — scheduled-event time expression

Aoi promised to call her mother on the half-hour after work.

Common collocations
  • at the half-hour
  • on the half-hour
  • past the half-hour
  • the half-hour mark
Synonyms
  • half past

    preferred in British-influenced time-telling; more common in speech than 'the half-hour'

  • thirty past

    used in American English time-telling; a direct alternative

Antonyms
  • on the hour

    the starting point of an hour, the opposite clock position

Grammar Patterns

at the half-hour

on the half-hour

past the half-hour

Common Mistakes

The train leaves on every half hour.
The train leaves on the half-hour.
Use the definite article 'the' when referring to the 30-minute mark of each hour.
I will arrive at half-hour past two.
I will arrive at half past two.' or 'I will arrive at the half-hour.
Do not combine 'half-hour' with 'past' like that.

Word family

  • half
    adjectiveA1
  • half
    pronounA1
  • hour
    nounA1
  • half-hourly
    adjectiveB1
  • half-hourly
    adverbB1

Synonym discussion

Sense: noun/1

Half-hour, half an hour, and 30 minutes all refer to the same length of time, but differ in how natural they sound in speech. Half an hour is the most common conversational form in both British and American English (I'll be back in half an hour). Half-hour often appears in compound adjectives (a half-hour show) or fixed expressions (every half hour). 30 minutes is more formal or precise and is preferred in schedules, timetables, and written instructions (the exam lasts 30 minutes). In Taiwan English teaching, half an hour is typically the first form introduced at beginner level.

half-hourhalf an hour30 minutes

Common collocations

Phrases

  • half an hour
  • on the half-hour
  • every half hour
  • at the half-hour
  • within the half-hour

Prepositions

Etymology

Old EnglishOld FrenchLatinEnglish

Half-hour comes from combining Old English 'healf' (meaning half) with Old French 'hore' (meaning hour), which itself came from Latin 'hora' meaning a fixed period of time. The compound has been in use since the 14th century.

First known use

15th century

15th century, in the meaning defined at sense 1