It’s official. As if it’s having been unofficial up until now has slowed or in any way impeded Twitter’s explosive growth in journalism circles.

The trendy, concise, and utterly-fab-dahling social media site, known best for its 140-character limitations in individual “tweets,” is duly noted in the new 2009 edition of The Associated Press Stylebook, in many ways the standard for journalists worldwide.

Along with the Middle Eastern eggplant dish, baba ghanoush (of “Seinfeld” fame), Twitter joins “texting” as a verb and a bunch of jargon from the financial collapse (think “collateralized debt obligations,” “securitization,” and other catchy/headliney terms) in making its Stylebook debut. The verbs “tweet” and “twitter” also are legit, according to the new style manual. Also new as signs-of-the-times: CEO and mpg as first references to chief execs and miles per gallon.

The guide sells through AP for $11.75 for member news organizations and college bookstores, and $18.95 for all us others, plus $5.95 shipping. on June 15 was selling it for $12.98 plus $4.98 shipping.