this has been driving me crazy for over a fortnight!

there are words and phrases that are used incorrectly that mean the opposite of what the speaker intends. there are other words and phrases that, over time, come to mean the opposite of what they originally meant. but then there are some words that exist with opposing definitions simultaneously, and they just blows my mind!



the word that started this whole investigation for me is the word biweekly. i have always used it to mean "every other week", usually in the context of a paycheck. but it hit me that i have actually used it to mean "twice per week," even in the context of of this blog (which i have referred to as 'biweekly')

as an adjective, it is officially defined as

• fortnightly; occurring every two weeks (a fortnight is a two week period)
  
• semiweekly; occurring twice a week

and as a noun:

• a periodical that is published twice a week or every two weeks (either 104 or 26 issues per year)

i know if i were expecting some periodical to arrive twice a week and it came with one fourth that frequency i would be upset.

this same idea applies to bimonthly, which can be used as a synonym to semimonthly, or to mean 'every other month'

what really made this interesting is that the same rule does not apply to years:

biannual can only mean 'twice per year (semiannual)' and if you wish to mean 'every other year' there is a seperate word: biennial. this is similar to centennial, millennial, and any number of latin numerical prefixes with the -ennial suffix (triennial, quadrennial, quinquennial...)

words like this are a great peculiarity in english and can come to be in many different ways. There are many names for these words: contronym, autoantonym, antagonym, janus word, or enatiodrome, and there is a surprisingly long list of english words that have two meanings that oppose each other.

some of my favorites:

• strike - in baseball means you missed the ball, literally a failure to strike.
• custom - means 'the standard of a society' or 'specially desinged; unique'
• dust - 'dust the mantle' (remove dust) or 'dust for prints' (apply dust)
• scan - 'examine closely' or 'look over hastily'