NEW YORK — A different kind of F-word is stirring a linguistic and political debate as controversial as what it defines.

The word is “fracking” — as in hydraulic fracturing, a technique long used by the oil and gas industry to free oil and gas from rock.

It’s not in the dictionary, the industry hates it, and President Barack Obama didn’t use it in his State of the Union speech — even as he praised federal subsidies for it.

The word sounds nasty, and environmental advocates have been able to use it to generate opposition — and revulsion — to what they say is a nasty process that threatens water supplies.

“It obviously calls to mind other less socially polite terms, and folks have been able to take advantage of that,” said Kate Sinding, a senior attorney at the Natural Resources Defense Council who works on drilling issues.

One of the chants at an anti-drilling rally in Albany earlier this month was “No fracking way!”

Industry executives argue that the word is deliberately misspelled by environmental activists and that it has become a slur that should not be used by media outlets that strive for objectivity.

“It’s a co-opted word and a co-opted spelling used to make it look as offensive as people can try to make it look,” said Michael Kehs, vice president for Strategic Affairs at Chesapeake Energy, the nation’s second-largest natural gas producer.

To the surviving humans of the sci-fi TV series “Battlestar Galactica,” it has nothing to do with oil and gas. It is used as a substitute for the very down-to-Earth curse word.

Michael Weiss, a professor of linguistics at Cornell University, says the word originated as simple industry jargon, but has taken on a negative meaning over time — much like the word “silly” once meant “holy.”

But “frack” also happens to sound like “smack” and “whack,” with more violent connotations.

“When you hear the word ‘fracking,’ what lights up your brain is the profanity,” says Deborah Mitchell, who teaches marketing at the University of Wisconsin’s School of Business. “Negative things come to mind.”

Obama did not use the word in his State of the Union address Tuesday night, when he said his administration will help ensure natural gas will be developed safely, suggesting it would support 600,000 jobs by the end of the decade.

In hydraulic fracturing, millions of gallons of water, sand and chemicals are pumped into wells to break up underground rock formations and create escape routes for the oil and gas. In recent years, the industry has learned to combine the practice with the ability to drill horizontally into beds of shale, layers of fine-grained rock that in some cases have trapped ancient organic matter that has cooked into oil and gas.

By doing so, drillers have unlocked natural gas deposits across the East, South and Midwest that are large enough to supply the U.S. for decades. Natural gas prices have dipped to decade-low levels, reducing customer bills and prompting manufacturers who depend on the fuel to expand operations in the U.S.

Environmentalists worry that the fluid could leak into water supplies from cracked casings in wells. They are also concerned that wastewater from the process could contaminate water supplies if not properly treated or disposed of. And they worry the method allows too much methane, the main component of natural gas and an extraordinarily potent greenhouse gas, to escape.

Some want to ban the practice altogether, while others want tighter regulations.

The Environmental Protection Agency is studying the issue and may propose federal regulations. The industry prefers that states regulate the process.

Some states have banned it. A New York proposal to lift its ban drew about 40,000 public comments — an unprecedented total — inspired in part by slogans such as “Don’t Frack With New York.”

The drilling industry has generally spelled the word without a “K,” using terms like “frac job” or “frac fluid.”

Energy historian Daniel Yergin spells it “fraccing” in his book, “The Quest: Energy, Security and the Remaking of the Modern World.” The glossary maintained by the oilfield services company Schlumberger includes only “frac” and “hydraulic fracturing.”

The spelling of “fracking” began appearing in the media and in oil and gas company materials long before the process became controversial. It first was used in an Associated Press story in 1981. That same year, an oil and gas company called Velvet Exploration, based in British Columbia, issued a press release that detailed its plans to complete “fracking” a well.

The word was used in trade journals throughout the 1980s. In 1990, Commerce Secretary Robert Mosbacher announced U.S. oil engineers would travel to the Soviet Union to share drilling technology, including fracking.

The word does not appear in The Associated Press Stylebook, a guide for news organizations. David Minthorn, deputy standards editor at the AP, says there are tentative plans to include an entry in the 2012 edition.

He said the current standard is to avoid using the word except in direct quotes, and to instead use “hydraulic fracturing.”

That won’t stop activists — sometimes called “fracktivists” — from repeating the word as often as possible.

“It was created by the industry, and the industry is going to have to live with it,” says the NRDC’s Sinding.

Dave McCurdy, CEO of the American Gas Association, agrees, much to his dismay: “It’s Madison Avenue hell,” he says.

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Jonathan Fahey can be reached at http://twitter.com/JonathanFahey.