biannual
What is the opposite of biannual? Here is what we hold, with its meaning and related words.
Adjective — Happening twice a year.
Synonyms by Meaning
1. adjective
Happening twice a year.
“The society holds a biannual meeting, once in spring and once in autumn.”
semi-annual
twice-yearly
half-yearly
biyearly
semiannual
2. adjective
Happening once every two years.
“The biannual festival returns in 2028 after a two-year gap.”
biennial
two-yearly
How to use biannual
The word patterns that sound natural to a native speaker.
biannual report
biannual review
biannual conference
biannual inspection
Because the word carries two opposite-sounding meanings, careful writers avoid it and say 'twice a year' or 'every two years' instead.
Etymology
From the Latin prefix bi- ('two') and annus ('year'), giving annual.
Full origin of biannual →Frequently asked questions
What is the difference between biannual and biennial?
Biennial reliably means once every two years, and it is the safer word for that meaning. Biannual is ambiguous: dictionaries record it as both twice a year and every two years, so readers cannot be sure which you intend. If you mean every two years, write biennial.
Does biannual mean twice a year or every two years?
Most often it means twice a year, and that is the sense listed first in most dictionaries. The every-two-years sense is also in genuine use, however, so the word alone does not settle the question. Always check the surrounding context or ask.
Is semi-annual the same as biannual?
Semi-annual is unambiguous and means twice a year, every six months. It is the better choice when you want that meaning understood without doubt.
