LOS ANGELES » On many nights this fall, it has been possible to tune in to broadcast network television during prime time and hear a character call someone else a “;douche.”;

In just the last several weeks, it has happened on CBS's “;The New Adventures of Old Christine”; and the CW's “;The Vampire Diaries,”; which are broadcast at 8 p.m., during what used to be known as the family hour. It has been heard this fall on Fox's new series “;The Cleveland Show,”; which begins at 8:30, and on ABC's “;Grey's Anatomy.”; On NBC, its use has spanned the old and the new, blurted out on the freshman comedy “;Community”; and the seasoned drama “;Law & Order: Special Victims Unit.”;

In total, the word has surfaced at least 76 times already this year on 26 prime-time network series, according to research by the Parents Television Council, which compiled the statistics at the request of The New York Times. That is up from 30 uses on 15 shows in all of 2007 and just six instances on four programs in 2005.

Ever since George Carlin laid out the “;Seven Words You Can Never Say on Television”; in 1972, television writers and broadcasters have been digging more deeply into the thesaurus, seizing on new ways to titillate, if not offend. And while the word “;douche”; is neither obscene nor profane—although this usage is certainly offensive to many people—it seems to represent the latest of broadcast television's continuing efforts to expand the boundaries of taste, in part to stem the tide of defections by its audience to largely unregulated cable television.

As a result, words that previously were rarely heard on television suddenly turn up everywhere, while once unspeakable slurs become passe from overuse. The use of the word “;bitch,”; for example, tripled in the last decade alone, growing to 1,277 uses on 685 shows in 2007 from 431 uses on 103 prime-time episodes in 1998.

The Parents Television Council is a conservative interest group that monitors (and opposes) profanity on television, but television writers themselves acknowledge that the language on networks has changed.

“;As a writer, you're always reaching for a more potent way to call somebody a jerk,”; Dan Harmon, the creator of “;Community,”; said about the word “;douche.”; “;This is a word that has evolved in the last couple of years—a thing that sounds like a thing you can't say.”;

It is not simply that the language is becoming more raw on broadcast networks but that the language, violence and sex that formerly was restricted to the 10 p.m. hour has migrated to earlier time slots.

Recent research by Barbara K. Kaye of the University of Tennessee and Barry S. Sapolsky of Florida State University found that in 2005 television viewers were more likely to hear offensive language during the 8 p.m. and 9 p.m. hours than at 10 p.m. Technically, there has not been a “;family hour”; since 1976, when the U.S. Supreme Court struck down the imposition of such a policy by the Federal Communications Commission. But broadcast networks observed the practice long after that.

No more, it seems. At a symposium sponsored last summer by a group of 40 national advertisers known as the Alliance for Family Entertainment, the heads of the major networks said the idea of a family hour was antiquated and did not fit how families consume television today. Nina Tassler, the president of CBS Entertainment, commented that shows like her network's “;Old Christine”; “;merely reflect a different family dynamic.”;

That dynamic includes the frequent use of profanities—broadly defined as anything from sexual and excretory words to milder words like “;hell.”; Kaye and Sapolsky found that their use on broadcast prime-time television jumped from a rate of 5.5 times an hour in 1990 to 7.6 in 2001 and 9.8 in 2005.

While the fastest growth was in the use of the stronger words, the term “;jackass”; has gained favor recently, appearing in 34 family-hour shows so far this year, up from 31 in 2007 and 27 in 2005. Other words have come in and out of favor: “;sucks,”; for example, appeared in 226 family-hour episodes in 2005, fell to 120 in 2007 and rose again to 232 so far this year, according to the council's research.

The only time in recent years that the instance of profanity briefly declined, Kaye said, was in 1997, shortly television ratings were put into place. Network officials say they continue to pay great attention to broadcast standards.

“;We are still in the line-drawing business,”; said Martin D. Franks, executive vice president for planning, policy and government relations at the CBS Corporation. “;We may not have a formal family hour at 8 o'clock, but we are trying to be respectful of our audience and who makes up our audience at a particular time of day.”;

Not everyone in the business agrees. Neal Baer, an executive producer of “;Law & Order: Special Victims Unit,”; said that because the series was repeated in syndication and on cable at all times of the day, the producers could not worry about what time something was going to be viewed. “;It's hypocritical to say that you have to have shows on broadcast networks at 10 but they run at 3 or 4 or 5 in the afternoon on cable,”; Baer said. “;Kids have access to cable.”;

Users of the recently popular word “;douche”; defend its use, noting that it was invoked, usually with the suffix “;bag,”; in the 1990s by the character Andy Sipowicz on “;NYPD Blue,”; an ABC series that frequently pushed the boundaries of network acceptability.

Timothy Jay, a psychology professor at the Massachusetts College of Liberal Arts and the author of “;Cursing in America,”; said the word has evolved to the point where it has lost much of its offensiveness. “;Vulgar slang has a way of waxing and waning, where we become desensitized to a word's earlier meanings,”; he said. “;I would bet most kids today couldn't tell you what a douche bag is.”;