Bi-annual or biannual?
bi-annual is an adjective meaning “Alternative spelling of biannual”; biannual is an adjective meaning “Occurring twice a year; semiannual”. Wiktionary gives them as spellings of the same word. bi-annual is written with a hyphen and biannual as one word; they are used differently.
What is the difference between bi-annual and biannual?
| bi-annual | biannual | |
|---|---|---|
| Part of speech | adjective | adjective, noun |
| Meaning | Alternative spelling of biannual | Occurring twice a year; semiannual proscribedOccurring once every two years; biennial Something occurring twice each year |
| Example | none recorded | none recorded |
| Pronunciation | not recorded | /bʌɪˈanjuːəl/ /baɪˈænjuəl/ |
| In writing | not counted (the list counts single words) | about once in every 3 million words |
Sources: bi-annual and biannual 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 bi-annual and biannual
bi-annual
- 1
Alternative spelling of biannual
biannual
- 1
Occurring twice a year; semiannual
- 2
Something occurring twice each year
- 3
proscribedOccurring once every two years; biennial
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, bi-annual or biannual?
bi-annual is a phrase, which the list of single words does not count; biannual about once in every 3 million words.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How many people search bi-annual vs biannual?
“bi-annual vs biannual” is searched about 10 times a month on Bing (Google reports it together with close variants, so it has no figure of its own) in the United States.
Sources: Google Ads keyword data through DataForSEO and Microsoft Advertising keyword data through DataForSEO, the average month from September 2025 to August 2026.