Biannual
The word is "Biennial".
if something happens to you it oviesly matters but it depends on what happens to you on what you do.
If it happens often, it happens commonly.
nothing
If something is biannual, it happens twice a year.
Biannual
twice-a-day or it can be called semi-diurnal which relates to such occurrences as tides.
You are looking for the words semi-annual, bi-annual, twice a year or seasonally.
bicentennial means when something happens twice in a year, or once every two years
An event of some sort that happens twice a year.
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If something happens twice a month it is called biweekly because it happens every other week and a month has 4 weeks. there is also bimonthly which is every other month but not really a direct word for something that happens twice a month.
the letter E
The letter E. wEEk and yEar.
When something happens 6 times per year, it is referred to as occurring "bi-monthly." This means the event or frequency happens every two months. It is important to note that the term "bi-monthly" can sometimes be ambiguous, as it can also mean twice a month in some contexts. To avoid confusion, it is best to specify whether it is every two months or twice a month.