Lay people never know which instrument to focus on where two or more jazz musicians are gathered, or what to call the group. Is it a piano trio, guitar trio, sax trio? In the case of three legendary sidemen gathered as a trio onstage at Seattle’s Jazz Alley Monday night, that’s an easy equation to figure out: Obviously it’s a drum trio, thanks to Bill Stewart foraging for uncharted territory on his kit.

Last night, Dimitriou’s Jazz Alley welcomed the drum trio of Stewart, Grammy-nominated keyboardist Larry Goldings, and guitarist Peter Bernstein — a rare feast for the senses around these parts, despite the group’s longevity (over 25 years).

While Goldings and Bernstein were on their game, switching comps and leads as astutely and seamlessly as the next leading artist, Stewart took his game to a whole other level.

Like a restless anthropologist in the jungles of the Amazon, or a mischievous sound effects engineer constantly tweaking the sets, Stewart kept the vintage feel of Bernstein’s introspection and the far-out tangents of Golding’s space-age voyages from lapsing into dangerously monotonous territory.

Stewart found the mark and riffed the bejsus out of it every time, whether he grooved on Goldings’ “kinda sciency” ode to sci-fi fiction writer Isaac “Asimov,” his own boogie woogie, time-traveling “Tincture,” or Jobim’s rare non-bossa-nova, “Luiza” (found on the trio’s hit 2014 album, Ramshackle Serenade).

In the Jazz Alley opener, Stewart transcended the guitar and the B3 — as a drummer — to bank off both the melodic atmospheric jazz intrinsic in such trios to the Never-Never-Land of dark, avant-garde and modern straight-ahead jazz.

Song after song, Stewart leveled the dainty structure of Goldings’ B3 and Bernstein’s guitar. A drummer, any drummer, could easily second-guess his place amongst such strong performers as guitarist Bernstein and organist Goldings with their frontburner, star instruments. Not this drummer.

Somehow, this drummer balanced his instrument’s tendency to easily overpower every other musician in the room on his boombox, with the balance of soft and hard hydraulics and knowing when to build the small moments into significant banter that brought out the other musicians’ active states, as well as calling attention to their inspirational, albeit disquieting, subdued notes by comparison.

On Peter Bernstein’s hypnotically thoughtful “Dragonfly,” a highlight of the night, Stewart connected the dots by providing important musical context, picking up the funky strain of Bill Withers’ 1972 hit single, “Use Me,” in Bernstein’s circling rhythm on the fade socked to the audience, who enjoyed every spare second. Stewart constantly spread out, a search party for new avenues of expression on the lengthy songs that primarily rode on the same guitar-organ vibe.

Then, on “The Acrobat,” the last song of the night, as Larry Goldings pumped out the reverb on his Hammond in a dirge only the lonely and circus clowns from the 25th century have ever heard of… Bill Stewart ambles by, flicking the lights on and turning up the contrast. Goldings’ song featured all three musicians doing their thing, three things going on at once, as they fought to converge forward to some finish line, charging for the tape — soft and hard, soothing and dynamic, a fascinating study in contrasts, in concert for those lucky and smart enough to attend.

Bernstein and Goldings didn’t disappoint, either, despite Stewart’s shining star. The quieter of the three, in person and in song, Bernstein nevertheless held the set together while inspiring a closer listen to the intensive intricacies of his gold-flecked, varying gradations of focus on a nostalgic run out of time — the sophistication to Goldings’ at times bawdy, raucous organ kissing cousin.

Goldings wowed with his ability to manipulate that instrument of ancient, sacred machinery. Fans know that he is arguably unsurpassed in his use of every possible combination of organic sounds. Almost every combination of sounds for every mood came out on opening night, as he jabbed, pulsed, and coaxed the condensed mass of “Asimov,” or imagined Stanley Kubrick’s “2001: A Space Odyssey” out of “Take Me Out To The Ball Game” and every horror intro in the silent movie era in the Sammy Cahn/Axel Stordahl standard, “I Should Care.”

The fourth song of the night revealed Goldings’ affection for “kinda sciency” instrumentals. It sounded exactly like the kind of instrumental HAL, the rebellious, heuristically programmed algorithmic computer, would make if he suddenly went haywire on astronaut Dave and tried to become a jazz musician (instead of take over the space ship).

Even more surprising, Goldings is hilarious as the emcee rambling about weird bugs and what a weird name Axel is. Before introducing Bernstein’s “Dragonfly” almost halfway through the set, Goldings riffed — ala early, absurdist Woody Allen — about the standard CD sales after the show. “We have CDs for sale. Not ours. We got some Wes Montgomery… Why am I still talking?... What do you feel like playing?... We’ve been playing together over 25 years… What do you feel like, Bill?” and then they were off again.

Definitely not your grandfather’s old music.