Karan Casey admits it: She was nervous.

Yes, she’s been performing for decades in front of audiences big and small, in her native Ireland, the UK, the US, and many other places. But at January’s Celtic Connections in Glasgow – one of the premier Celtic music events in the world – she was about to unveil a brand-new song of hers, one unlike any other she’d written, let alone sung; she had recorded it for her new album, “Nine Apples of Gold,” but hadn’t yet performed it in public.

“I Live in a Country” is no sweet lullaby, no tender love song. It’s meant to be angry and sounds it, with a persistent drum rhythm and haunting keyboard backdrop throughout. The lyrics, mostly spoken – Pauline Scanlon joins her on the vocals – are a no-holds-barred denunciation of the wrongs perpetrated against Irish women down through time (“We are the daughters of the witches you could not burn for centuries/We are the daughters of the Magdalene laundries/When you had us down upon our knees/We are the daughters of the mother and baby homes/Where you did what you pleased”), as well as an affirmation of women’s resilience in spite of it all – and a declaration, punctuated by an expletive, that it is past time for women to be patient and hold their collective tongue: “Some days I want revenge but most I fight for equality.”

Casey hadn’t intended to present “I Live in a Country” at Celtic Connections. But Niamh Dunne, her fiddler and co-vocalist for the event, urged her to do it, with Dunne taking Scanlon’s part. Casey agreed.

The reaction from the audience, recalls Casey, “was unbelievable. Completely different than what I expected. I felt such a release.” She continues: “I had worried that people might focus more on the anger, and the swear word, in the song than on why the anger is there, and why that word is used. Women, after all, have always been told that we ‘have to be nice’ – especially women who are singers and musicians. I think of women like Nina Simone, who didn’t stay silent, who didn’t just ‘be nice,’ but showed that it’s okay for a woman to be angry and express it. I guess it took me longer.”

Casey will formally introduce her Boston-area following to “I Live in a Country” and the rest of the new album at Harvard Square’s Club Passim on March 5 at 8 p.m. (UPDATE: a 5 p.m. show has now been added), where she’ll be accompanied by fiddler Sheila Falls, the director of Irish music programs at Boston College (including its Gaelic Roots series), and guitarist Matt Heaton.

By now, anyone familiar with Casey's body of work knows that she has multiple interests that go beyond music – and as for music, well, she's had a lot going on there as well, going back to her foray as co-founder and lead singer for groundbreaking Irish-American band Solas and winding through a solo career that's seen her show her chops in jazz, rock, and pop as well as traditional and contemporary folk. And then there's her trajectory as a songwriter of depth and a 360-degree circle of vision to boot, as "Nine Apples of Gold" demonstrates; multi-instrumentalist Sean Óg Graham – who, along with Dunne, is a member of the quintet Beoga – is co-author with Casey of five of the 10 songs on the album, “I Live in a Country” among them.

 Casey is not one to compartmentalize her art from her emotional and spiritual side, often using one to inform the other, and her various activities and projects also seem to play off one another as well. Her 2008 album, “Ships in the Forest,” for example, spoke to what she saw as an unresolved grief about Ireland’s past traumas and injustices, and the continuing revelations and controversies such as the Magdalene laundries and mother and baby homes have been much on her mind. 

All this, along with her advocacy for gender balance in the production, performance, promotion, and development of Irish folk and traditional music, notably by her championing of the FairPlé (Fair Play) campaign – which sparked a wider conversation about sexual harassment and assault in Irish music circles – led her to consider the marginalization of women in a wider context of Irish society and history. She gave expression to these ruminations in her stage show, “I Walked Into My Head,” that she premiered at the Kilkenny Arts Festival last year, part song-poem and part music performance – from which some material wound up on “Nine Apples of Gold.” 

If that isn’t enough, she’s been in the process of researching and writing a book about her great-grandmother, Agnes O’Dwyer, who was part of the Cumann na mBan, a revolutionary group of Irish women in the early 1900s – and, of course, this project also has stoked her contemplations on history, personal, familial, and large-scale.

But “Nine Apples of Gold” is not so much about conflict or hardship as it is about how we, as humans, respond to it – or anything in the realm of human experience, for that matter, says Casey.

“I’ve always felt songs sing what we can’t say. In these songs, I’m talking about how we heal, how we join together to overcome that which oppresses us or makes our lives difficult, how we can renew ourselves. A big part of that is opening ourselves up to own insecurities, and for myself I found healing in the natural world, leaning into things that perhaps we can’t quite understand or explain – being strong, being defiant but also allowing yourself to be open, even vulnerable.”

The title track, which opens the album, encapsulates all that: Casey drew inspiration from the legend of Tonn Chlíona, a supernatural woman from Glandore said to have three songbirds who ate apples from an otherworldly tree and whose singing could cure all illness; her powers caused an uproar, but Chlíona changed into a wren to escape the men who set out to kill her. The song, set to a gentle melody and 3/4 time, describes Chlíona’s good works – putting bread “in the hands of the hungry and tired,” and “loving with all her might” – and the chorus offers a benediction: “Hear the music how it heals.” At the end, there’s a recording of songbirds from Portglenone Forest in Antrim, courtesy of Graham (one of numerous contributions he makes to the album). 

“I loved the magic in this story and thought a lot about how women carry tunes and songs and dance and bring so much healing to the world,” says Casey, who provides piano accompaniment on the track.

“Daughter Dear” exemplifies the influence of traditional song idioms on Casey, in this case a mother-daughter conversation from the grave, all tenderness and regret (“What is it you wish to whisper/In my small round ear/Mama my dear?”), accentuated by Rioghnach Connolly’s harmony vocals and more fine piano from Casey. “Return to the Wild” also has references to the folk song lyric tradition (“Do you hear the ships sail in the forest/Do you hear the strawberries grow in the salt sea”) in its extolling of the natural world’s virtues, and there’s a bit of folk wisdom, too: “If you let sorrow come in on you/He will come and stay/He will sit down to wine and dine/And he won’t go away.”

“The Weeping Time” shifts not only mood and tone but sense of place, as Casey evokes the story of the Gullah Geechee people from the coastal areas and the sea islands of North Carolina, South Carolina, Georgia, and Florida, who have strived to maintain their African heritage and culture. Graham’s finger-picked acoustic guitar gives the song an appropriately American South flavor, and the lyrics convey history and legacy : “Time steps onto the train/Time with her dominant refrain/How many drowned/How many survived/How many were caught again/If the water could weep/If the dogs could speak.”

Solidarity and camaraderie fire country-rockish “Sister I Am Here for You,” driven by Graham’s acoustic and electric guitars and John McCullough’s keyboards, and most of all, Dunne’s backing vocals on the chorus and the proclamational ending: “Deep down in our bone we know times are going to change.” Casey is quick to credit Graham for the song’s musical character, which came from listening to some of recent Grammy winner Bonnie Raitt’s discography.

“Sean and Niamh both have been such a pleasure to work with,” says Casey. “We have quite a bit in common: We like a lot of the same things, and we come from the tradition, so there are a lot of places where we overlap. But, being 15, 17 years younger than me, they have fresh ears and fresh perspectives, and I like having that dynamic when we collaborate.”

Casey’s rendition of the album’s lone traditional song, the much-covered “The Rocks of Bawn,” is a revelation. As a “come-all-ye,” there is an implicit sense of shared struggle and fellowship to it, but also an undertone of melancholy resignation (“I’m afraid you’ll never be able to plough the Rocks of Bawn”), underscored by Graham’s spare, bright guitar.

Having gone through a spectrum of emotions on the album’s first nine tracks, Casey sews it all together with “I Thank My Lucky Stars,” an affirmation, and appreciation, for the things we have in front of us – whether birds, trees, and sunlight – and inside us, including music and even “sorrows left unsaid.” So perhaps it’s not surprising that she dedicates the song to daughters Mauireann and Áine (the latter of whom conceived of and performed in a dance piece for the “Nine Apples of Gold” video).

Having previewed a few selections from “Nine Apples of Gold” during her US tour last September, Casey looks forward to bringing out all the new material, and some of the old, during the 13-city tour – including the stop in Boston – in March.

“You can get so much energy back from performing,” says Casey. “It’s great to be at the stage where you just enjoy yourself being out there. If you really care about what you do, if you really want to be good, playing music for a living can be overwhelming at times. But when you’re actually in front of people, that’s when good things can happen: I think of music as an in-between time and space where we can talk about difficult and thorny subjects; we can put these subjects into the room in an easier way, through the words and melody of a song.”

Tickets and other information for Casey’s March 5 show at Club Passim is available at passim.org. For more about Casey and “Nine Apples of Gold,” see karancasey.com.