Heat wave or heatwave?
heat wave is a noun meaning “A period of exceptionally hot weather”; heatwave is a noun meaning “Alternative spelling of heat wave (“period of exceptionally hot weather”)”. Wiktionary gives them as spellings of the same word. heat wave is written as two words and heatwave as one word; they are used differently.
What is the difference between heat wave and heatwave?
| heat wave | heatwave | |
|---|---|---|
| Part of speech | noun | noun |
| Meaning | A period of exceptionally hot weather USThree consecutive days with daytime high temperature of 90 degrees Fahrenheit or higher | A heat haze |
| Example | none recorded | none recorded |
| Forms | none | heatwaves |
| Pronunciation | /ˈhit weɪv/ | /ˈhitˌweɪv/ |
| In writing | not counted (the list counts single words) | about once in every 1 million words |
Sources: heat wave and heatwave in the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
Every current meaning of heat wave and heatwave
heat wave
- 1
A period of exceptionally hot weather
- 2
USThree consecutive days with daytime high temperature of 90 degrees Fahrenheit or higher
- 3
UKA period of at least three consecutive days with daily high temperatures of the respective county's temperature threshold or higher
- 4
An electromagnetic wave in the infrared spectrum
heatwave
- 1
Alternative spelling of heat wave (“period of exceptionally hot weather”)
- 2
A heat haze
Source: the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); obsolete, archaic, dialect and rare senses left out.
Which is more common, heat wave or heatwave?
heat wave is a phrase, which the list of single words does not count; heatwave about once in every 1 million words.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).