WASHINGTON — Thousands of music lovers are expected to attend Hanukkah parties in cities worldwide tonight, marking the Jewish holiday by dancing to klezmer-punk, hip-hop in Arabic and folk-rock tunes such as "Applesauce vs. Sour Cream," a campy song about condiments for latkes, a potato pancake that is a Hanukkah staple.

The parties are being put on by JDub Records, a Jewish label. The Eight, JDub's name for the multi-city event, is expected to be the biggest contemporary Hanukkah music happening in North America, drawing about 7,000 people. Cities were still being added and listed on http://goeight.com.

The Jewish music industry has flourished over the past decade and uses Hanukkah, a minor religious holiday that began Tuesday night at sundown, as a time to party.

While still tiny in the grand scheme of the overall music business, the movement that some call "new Jewish music" is seen by musicians and fans as thriving. It uses sounds and lyrics and language from the Jewish world present and past. Three labels have started since 1995, including JDub, which opened in 2002 and produced Hasidic reggae star Matisyahu as well as the rock band LeeVees, which is made up of Jewish members of better-known bands and has sold over 10,000 copies of its 2006 album, "Hannukah Rocks."

While the industry and shows go on all year for such bands, the Hanukkah is a key time in the United States because of the Christmas-driven party season. Last year, XM Radio launched a Hannukah station (which runs for the holiday's eight days), and with the increase in contemporary Jewish bands, more concert halls and bars are hosting Hannukah music parties each year.

The proliferation of music has raised a broader question: What is Jewish music? Unlike the Christian music world, most of what's coming out is not God-worshiping. Some bands have Jewish members. In other cases, musicians may be non-Jews, but the words, sounds or performance styles are inspired by Jewish history. Much of it is a blend.

Jacob Harris, JDub vice president, said bands that sign with the label have to be able to proudly explain the link between their music and their Jewishness. (Although, he says, "we leave the identity part to the artist.") But for the Hannukah shows, the connections can be a lot looser.

"They have to feel like they want their music to be played at a Hanukkah party. And that they can be a part of that, and it's not too esoteric," he said.

The what-is-Jewish-music debate is common in Jewish publications and music blogs, including Tzadik, a label started in 1995 by John Zorn, a composer and saxophonist who won a MacArthur Fellowship last year for nurturing and creating experimental music.

"I do not and have never espoused the idea that any music a Jew makes is Jewish music, nor do I pretend to be the sole arbiter of what is Jewish or what is not," he wrote last year in an essay posted on his site about artists he supported. "Clearly the inclusion of music with no overt Jewish content may seem out of place in a series dedicated to Jewish music and it is very gratifying to experience the power the word (or the image) continues to exert on the human spirit. The operational word here is 'music.' "

Those inside the new Jewish music boom find it rewarding to see bands stretch so far beyond old-country wedding and bar mitzvah music, to lose what Harris calls the once-prevalent stigma of being "Jewish bands" or affiliated with a "Jewish label." Now people talk about the opposite: bands getting consumed with hipness and being consumer-friendly.

This means opting for the trendy over the more musically complex, the ironic over the emotionally sincere.

"I worry sometimes when things get trendy and when artists start making art to fit hipster expectations, that it can be reduced to more Jewish jokes, good fodder for a party," said Josh Kun, a communications professor at the University of Southern California and a co-founder of Reboot Stereophonic, a Jewish label founded in 2005. "But I think the majority of stuff is earnest."

Part of the reason this can all go on at Hanukkah is because the holiday is generally void of religious significance. A historic commemoration, Hanukkah marks the Maccabees' successful revolution against Assyrian-Greek religious persecution nearly 2,200 years ago. It is marked primarily at home, not in a synagogue, with lighting of candles and the playing of games that allow the retelling of the Maccabees' story. The holiday commemorates the rededication of the temple in Jerusalem after its desecration by foreign fighters.

Its timing near Christmas has turned it, primarily in the United States, into a much larger event.