Bi vs. Semi (weekly/monthly/annually)
Using bi or semi in front of time periods can cause tremendous confusion.
Biweekly means once every two weeks or twice a week.
Bimonthly means once every two months or twice a month.
In addition, a biweekly publication is issued every two weeks and a bimonthly publication is issued every two months.
Semiweekly means twice a week.
Semimonthly means twice a month.
To avoid confusion, you may want to substitute the actual time frame for these confusing terms.
For example, say, “I visit my aunt every two weeks,” not “I visit my aunt bimonthly.” If you mean every two weeks, you may also say, “I visit my aunt semimonthly.”
August 3, 2008 at 7:55 am
Anyone who actually says “I visit my aunt semimonthly.” should be taken out and shot!
August 3, 2008 at 5:16 pm
You have a point, Eric.
July 16, 2009 at 3:03 pm
how can this be accurate?!?!?!:
Biweekly means once every two weeks or twice a week.
Bimonthly means once every two months or twice a month.
It seems to me that this confusion is perpetuated by “authorities” who have accepted the generally misunderstood use of the words. This definition below actually has some merit and should be taught by all:
http://www.elearnenglishlanguage.com/difficulties/bisemi.html
The English prefixes bi- and semi- are often mixed up by native speakers. A semi-annual reading of this lesson will help more than a bi-annual one.
Bi-
Bi- comes from the Latin meaning two. When used with a temporal word, bi- means “every two” or “every other.”
This magazine is published bi-weekly, on the 1st and 15th of the month.
Congressional elections are held biennially, on even-numbered years.
The U.S. celebrated the bicentennial of its 1776 founding in 1976.
Semi-
Semi- comes from the Latin meaning half. When used with a temporal word, semi- means “twice.”
Our semi-annual meetings are in January and July.
I get paid semi-monthly, on the 5th and 19th of each month.
The semi-weekly deliveries occur on Monday and Thursday.
The Bottom Line
The confusion between bi- and semi- occurs because both prefixes are related to the concept of two. But bi- means something that happens every other (week, month…), or every two (weeks, months…), while semi- indicates something that happens twice every (week, month) or every half (week, month).
July 17, 2009 at 7:48 am
I agree with you wholeheartedly that the distinctions between “semi” and “bi” should be kept; however, because people confuse the two, the language has evolved (devolved) such that these prefixes are now often synonymous. By the way, you presented a very well-written argument!
July 13, 2010 at 1:08 pm
The original post is wrong and has just confused any reader.
Biweekly DOES NOT MEAN twice a week. Twice a week is SEMI-WEEKLY.
BI = every two
–Bi-weekly = evey two weeks
–Bi-monthly = every two months
–Bi-yearly = every two years
Semi = half
–Semi-monthly = twice per month (roughly every two weeks in perspective to a month, meaning it is not exactly 14 days)
–Semi-yearly = twcie per year (every 6 months)
July 13, 2010 at 7:13 pm
The prefix “bi-” has taken on both meanings: every two and twice. Therefore, one must now EXPLAIN oneself when writing or saying an expression such as “bi-weekly.” Please don’t blame the messenger (me) for this unfortunate development.