Beth Swick was a 40-year-old atheist with warm childhood memories of singing in the church choir when she found herself drawn by a one-word event notice taped to a door: “Chanting.” Inside, she found something called a kirtan, or group devotional music.

That experience 12 years ago — joining a call-and-response song in the unfamiliar holy language of Sanskrit with a group of strangers and a beautifully voiced leader — blew the doors of nonbelief off the disaffected Presbyterian.

For decades, Swick had thought that she wasn’t religious unless she identified with “some man-God off in some alternate universe in the sky somewhere.” Yet in that room, enveloped by the rich music and the group repetition of a single sacred phrase (although at the time indecipherable to her), Swick felt powerfully connected to something divine.

She was soaring.

She was praying.

“It was an expression of a feeling there wasn’t room for in my life at the time, some of those feelings of praise. Where does the word ‘praise’ fit into an atheist’s life?” said Swick, a project manager for architecture and design firms in Montgomery County who no longer considers herself an atheist.

After a few years of seeing kirtans only sporadically in the Washington area, Swick launched a monthly one in 2009. Today, there are about 15 such groups meeting regularly in the region; one can find several kirtans most weekend nights, held in homes or yoga studios. Last February, Sirius XM Radio launched a channel largely devoted to kirtan-style chant, which has morphed to include hip-hopper MC Yogi (whose popular chant-songs include “Ganesh Is Fresh”). Some 4,000 people come each January to the California desert for a four-year-old Zen-out called BhaktiFest that’s heavily centered on kirtan.

Kirtan — its pronunciation varies — may be the prayer of the spiritual-but-not-religious, America’s fastest-growing faith group — a way back to God through ecstatic experience rather than the passive intellectualism that institutional faith has become for many.

No doubt, sitting on the floor chanting Sanskrit phrases under soft lights isn’t for everyone, but it’s for a lot more people than it was a few decades ago, when Sanskrit chanting was reserved for the Hare Krishna. Demand is suddenly so great that kirtans are being offered at many local studios for yoga, which, like meditation, has become a gateway to the transcendent for millions of secular Americans who still, in some quiet corner, believe in God.

Some spiritual leaders see kirtan’s rise as a wake-up call to much of denominational religion. It fills a need to experience the divine. In with the intense, personal God, out with the aloof, remote one.

Gil Steinlauf, rabbi of Washington’s largest synagogue, Adas Israel in Northwest, said he is revamping its daily prayer meeting to include a chant on one psalm. He is also highlighting medieval call-and-response poetry during the high holidays.

“We are in the process of a paradigm shift, and kirtan represents that. The role it plays is very much in sync with the elements of Judaism we need to return to,” he said. “There is something extraordinary that happens when you have prayer or chanting that is a deep, implied relationship between leaders and people who are singing back and forth to one another. In that relationship, there is a profound sense of connection and interconnection that is transformational. That’s the experiential thing with kirtan.”

Devotional chant, of course, is not exclusive to Indian culture or Hinduism, of which kirtan is a part. Gregorian chant, typically associated with the Catholic Church, is centuries old and experienced a popular surge in the 1980s and ’90s, thanks to a rightward tilt in the church and New Age enthusiasts, as well. Buddhism, Islam and Judaism have their own chants, but the boom in fascination with Eastern culture has produced such people as Rabbi Andrew Hahn, a.k.a. “The Kirtan Rabbi,” who leads dozens of transfixed Jews with Indian music and holy Hebrew phases.

Kirtan is translated sometimes as “to repeat” and sometimes as “to praise that which is exalted.” The most common chants are different Sanskrit names for God. While it began as a mode of worship, for most practitioners today, going to a kirtan has nothing to do with embracing or even learning any particular theology. Most people don’t know the literal meaning of the chants. They come to be part of a powerfully emotive, spiritual, communal musical event.

“You know the part of the rock concert where everyone knows the words? It’s like that, but for the whole time,” said Gaura Vani, a 35-year-old Silver Spring dad and freelance filmmaker who grew up in the Hare Krishna movement and is now a well-known kirtan performer. “They say one of the sources of trauma is feeling no connection between you and other parts of humanity. When you do chant and mantras, it’s impossible to avoid the group connection, the sense of communion.”

A kirtan feels like the merger of a seriously groovin’ music show and the liveliest worship service you ever went to. It’s perhaps the only place in American life that combines yoga pants with the eyes-closed, arm-extended hand-waving praise of evangelicalism. This participatory, emotive expression isn’t an accident: Evangelical churches until recently were among the few growing segments of American religious life.

The similarity isn’t lost on the people who do it. One recent Saturday night, more than 50 people packed into a second-floor Dupont Circle yoga studio to hear lawyer-turned-yogi David Newman, a kirtan celeb. Some danced; others sat on the floor swaying and smiling. The event’s volume knob seemed to go from low-level joy to full-on bliss — the kind you feel after climbing a gorgeous mountain or ending a tough run on a strong sprint. Strangers hugged and danced wildly.

Twenty-three-year-old Gaithersburg athletic trainer Sha Golanski was among those who took the microphone for a turn of “He Ma Durga,” a Sanskrit chant to maternal love. Having grown up in a charismatic Assemblies of God church, the kirtan’s call-and-response style felt familiar, he said.

“It fulfills a very basic need — to come together, to share something as a group,” he said. The fact that he didn’t know the mantra’s meaning wasn’t important, he said.

Golanski is like many kirtan attendees, people who fell away from their childhood faith but still seek ways to experience the divine. The swath of America that has no particular religious affiliation — but that rejects “atheist” or “agnostic” labels — has stretched from 8 percent in 1990 to nearly 20 percent today. This is kirtan’s market.

“Human beings need ecstasy. And this is like taking holy communion. It has the quality of evoking joy,” said Grace Ogden, a former conference director at Washington National Cathedral who produces events independently now and calls herself a “Buddhapalian.”

Ogden, 51, has participated in kirtans for years and says she doesn’t know the translation of every chant. The power, she says, is in knowing that the words are ancient and holy.

“Kirtan is where yoga and religion come together,” said Hari-kirtana Das, a yoga and kirtan teacher who lives in Northwest. He calls kirtan “the most accessible way to get into the spiritual aspect of yoga.” While many yoga teachers try to weave a few minutes of yogic philosophy in with the tush-tightening poses, kirtan is more accessible because it’s experiential.

“What makes the sound powerful is when it’s transcendental. And what is it about the name of the Lord that makes it holy? The sound itself is spiritual,” he said. “When we sing kirtan, we’re not singing about ourselves, we’re singing about a supreme being who we have a relationship with.”

At Newman’s kirtan and another on the same night, farther north in Washington, photos of Indian saints or the Dalai Lama were displayed on low tables. But such details are increasingly meaningless to a more pluralistic America that sees many ways to grace and ritual and divine ecstasy.

To Swick, kirtan was a path back to God.

“Through this practice, I’ve come to believe that God is not some separate thing from us,” she said, “and to be grateful to something larger in my life.”