If I check in with livejournal only twice a year...

[hauntmeister]

is it biannual, or semiannual?

Comments

[ron_newman]

semi-annual = every semi-annum = every half-year = twice a year

bi-annual = every bi-annum = every two years

[ceo]

Biannual apparently can mean either depending on whose dictionary you ask, and is therefore deprecated. So, semi-annual is twice a year as Ron noted; biennial is every two years.

[ron_newman]

bimonthly and biweekly seem to cause similar confusion. Periodicals published every two weeks sometimes use 'fortnightly' instead.