The art of temporally arranged sound: that’s more or less what most formal definitions say counts as “music.” A vague idea, sure, but those faceless dictionary writers are trying to take into account the widely varying standards people use — some demand a clear melody; some require an established rhythm — to separate what they actively listen to from what they simply hear.

But no matter how you define music, Weirdo Records in Central Square can offer up something from its world-spanning collection of out-there albums to push the boundaries even farther, from Swedish noise rock to ambient recordings of laboratories.

The tiny shop has been pushing the most eclectic, rare, and all-around strange recordings for two years now. This anniversary is one that owner and sole staffer Angela Sawyer sees as cause for celebration, considering the shop’s narrow appeal and the music industry’s shakiness.

But even from the start, Weirdo’s fittingly nontraditional journey has been a testament to the idea that even the most bizarre stuff has relevance and appeal in Boston’s culture.

Sawyer, who performs in several local experimental music acts, first started Weirdo in 2006 as nothing more than a website and a mailing list. But the project generated so much interest among Boston sub-cultural fanatics that she began allocating hours for people to browse records in her apartment. As Weirdo’s fanbase continued to grow, Sawyer eventually decided she needed more room.

Despite some skeptical friends and her own low expectations, Sawyer continued with her plan for an actual storefront, and subsequently found herself once again shocked by the reaction. The store has become a hub for the Boston area’s experimental music scene, thanks not only to the rarity of its content, but also its essentially ever-open doors: Weirdo is even open on most holidays, when customers are frequently treated to snacks and screenings of obscure films.

Anyone who has been inside Weirdo’s current location may have trouble believing that it was much

of a spatial upgrade — the shop’s website does not exaggerate when it describes the store as “smaller than the average dorm room.” But Sawyer says it has made a big difference.

“I had about this much room before, but I had a couch and television set,” she told the Beacon. “And roommates.”

Now two years in and still thriving, Sawyer is preparing to celebrate both Weirdo’s success and the enthusiasm of Boston’s deep underground scene — from the esoterically-inclined record collectors, to the appreciators of rare cinema, to the local noise-creators and performers themselves — with a birthday concert.

The lineup for the Feb. 5 bash, in order to acknowledge the theme of “two,” comprises several duos — some of which have taken part in Weirdo’s Series on Mondays, the shop’s weekly program that draws in-store performances by artists whose niche appeal make them unbookable at many area venues.

The anniversary event will take place at the Whitehaus, a junk-covered Jamaica Plain residence that several area musicians call home, and it really couldn’t be anywhere else. The dwelling’s frequent house concerts and its dismantling of the traditional performer-audience dynamic have made the Haus a sort of counter-cultural Xanadu among Boston music fans. Though yowling, stomping hootenannies are the specialty, any outsider art — including free-form poetry, performance art, experimental film, and combinations of those three — has a place at the Whitehaus.

With the concert, Sawyer hopes to strike down barriers within the scene itself. The lineup — handpicked by Sawyer — features acts of deviating styles that usually wouldn’t be seen on the same bill. Indeed, Neptune’s homemade scrap-instruments and dizzying tremors of noise are a far cry from Cotton Candy’s whimsical and shiny power-pop.

The bill’s stark contrasts highlight a key message of Weirdo: that even the most outlying music can have a unifying power.

“For the general population — people who only pay as much attention to music as I do to shirts — there’s this idea that this music is difficult,” Sawyer acknowledged. “I understand not everyone is going to be interested in a recording of someone banging their own head with a kitchen pot.”

To break down the stigma, Sawyer actively promotes an “unsnooty” attitude in the store. Listening to “weird” music, she says, isn’t about trying to be challenging: it’s about being open.

“I’m most interested in not having fences inside my head about what I listen to,” she described. She sees herself in an ongoing quest to explore what makes a recording, regardless of genre or era, have quality. “I feel like that’s a project that anyone who wants to can work on.”

And Weirdo Records seems like the ideal headquarters for that mission — everyone is welcome, they just might not be able to fit.

Weirdo Records (844 Massachusetts Ave., Cambridge) is open 11 A.M. to 9 P.M. all week long.

The shop will host its second birthday party at the Whitehaus (10 Seaverns Ave., Jamaica Plain) on Feb. 5.