Madonna. (Michael Sohn/Associated Press)

The curators of the National Portrait Gallery exhibition “American Cool” came up with 100 names with which to define the concept. But they didn’t stop there. How could they? The idea is so powerful yet amorphous that there’s almost no containing it. So they also came up with another 100 names for a supplemental list (in many cases including people who would have been in the top 100, but for want of a truly iconic “cool” photograph).

Because the names on both those lists come from a wide range of disciplines — acting, music, literature, dance — we asked some of our own critics to have a say. Here are their quick takes for an essential primer in who’s cool:

Peter Marks, theater critic

Kim Stanley: Canny Broadway actress whose work (“Bus Stop,” “Picnic”) pegged her as a serious interpreter as well as a star.

Stella Adler: The veritable soul of the Group Theater, whose acting classes became the Epicenter.

David Mamet: Playwright whose foul-mouthed, benighted characters were manna to angry young actors (and audiences).

John Malkovich: Embodiment of the rebel acting spirit of the upstart and influential Chicago school.

Savion Glover: Serene dancer who made Broadway hip for tap.

Ron Charles, book critic

The Library of America recently published a volume called “The Cool School: Writing From America’s Hip Underground.” It includes all the requisite literary lights — Jack Kerouac, Henry Miller, William S. Burroughs — and other writers who are a lot more fun to remember than to read. It’s probably a symptom of chronic squareness, but I prefer today’s cool writers: genre-breaking storytellers with extraordinary skill who make it all seem effortless:

Michael Chabon : With his dazzling, acrobatic style, Chabon celebrates vintage comic books and record stores.

Jennifer Egan: Her Pulitzer Prize-winning novel, “A Visit from the Goon Squad,” intermixes literary forms in a jazzy tour-de-force.

Dave Eggers : His brilliant memoir, “A Heartbreaking Work of Staggering Genius,” marries irony and poignancy as only the coolest writers dare.

Neil Gaiman : In books, comics and graphic novels for children and adults, Gaiman transforms his nerdiness into rarefied coolness.

Colson Whitehead: This MacArthur genius writes with a wry smile about everything — including the zombie apocalypse.

The truly cool don’t care about such arbitrary rules, of course, but for this list I restricted myself to American writers (sorry, Murakami), considered only living authors (we still miss you, David Foster Wallace), and selected from novels I’ve actually read, instead of from those I coolly pretend to have read (let this be our secret, Chuck Palahniuk).

Chris Richards, popular music critic

Prince: If we define coolness as that magical confluence of excellence and unknowability, the purple mystery man is coolness incarnate.

Lou Reed: He didn’t invent cool, but in rock-and-roll, he stands as the archetype.

Billie Holiday. Her cool feels truly eternal.

Miles Davis: He’s the man responsible for the “Birth of the Cool.” But he ran hot, too.

Neil Young: Bottomless intensity plus uncompromising focus equals cool.

Hank Stuever, TV critic

Jon Stewart: What’s cool is how he convinced everyone that they weren’t really getting the truth about important news until they watched his take on it. He got cool while everyone in Washington got more and more uncool — journalists especially, who rewarded him with untold envy and great press.

Madonna: Can her coolness be better summarized than it was by Joan Cusack’s character in the 1988 movie “Working Girl?”: “Sometimes I sing and dance around the house in my underwear. Doesn’t make me Madonna. Never will.” (Now we’re at a point where even Madonna wishes she was Madonna.)

Joan Didion: Merging onto freeways in that yellow ’69 Corvette Stingray of hers, staving off migraines and anxiety attacks, the coolest writer on the planet. Decades later, the band Cold War Kids name-checked her in a song called, appropriately, “Santa Ana Winds”: “In between is a basin like the great divide, where the 110 swallows the 105; Chutes and ladders leaving me where I begun, like J-J-J Joan Didion. . . .

Hunter S. Thompson: Nothing like the glint in the eye of the young male undergrads (always the guys) who have just discovered Hunter Thompson. I remember them in journalism school — awake at last and ready to write. It still happens.