Bimonthly or Semimonthly?

The most recent issue of MIT's Technology Review arrived on my proverbial doorstep the other day. This issue happened to include a notice to subscribers kindly explaining that Technology Review is moving to a more web-focused publication regimen, and will therefore be reducing its hard-copy publication frequency to "bimonthly".

My first thought upon reading this, "Oh — how often did it come before?", was followed promptly by a second, "Er — how often is bimonthly?" Please, if you will, suspend your smug re-assessment of my intelligence and bear with me.

The prefix "bi-", from the Latin, means "two" — simple as that. Bimonthly, then, is either 'two-monthly', as in 'every two months', or 'two, monthly', as in 'twice each month'. But which?

This, friends, is one of the many instances where the English language, by flaunting logic and regularity with head held high, reminds one not to get too comfortable. And I quote:

bi‧month‧ly

1. Happening every two months.

2. Happening twice a month; semimonthly.

Whose brilliant idea was that? It's one thing for a word to be confusing because of widespread incorrect use (e.g. irony), but quite another for a word to be defined in a confusing manner.

Furthermore, you'll notice that the definition above cites the second meaning of bimonthly as being synonymous with "semimonthly".

The prefix "semi-" is, like "bi-", derived from the Latin, and means "one-half". If there were any fairness in the world, "semimonthly" would be defined in as confusing a manner as "bimonthly", but, alas, English once again gives us the finger:

sem‧i‧month‧ly

Occurring or issued twice a month.

And the only thing worse than the ridiculousness of 'two-monthly' being synonymous with 'half-monthly' is, of course, that they only sometimes mean the same thing — it's not even consistent! Help!!

The Wiktionary entry on "bimonthly" features a similar definition, and also a usage note stating, in all seriousness, that:

"Because of the ambiguity of this word, it is best to avoid it."

This is clearly madness, and so, dear Reader, it's time for us to Fix It — ambiguity is just one more form of Drag, and you know how we feel about that around here. From now on, we are going to use "bimonthly" to mean exclusively "occurring every two months" (definition 1, above) and "semimonthly", well, we'll just use that correctly. If and when you come across either of these terms being used incorrectly in the wild, please go out of your way, if possible, to (gently!) correct the offending individual or publication.