It was the second-to-last weekend of the regular season, a pivotal moment for baseball’s pennant races. Pitching was scrutinized. Analysis was deep.

“His stuff was really good,” Chicago Cubs manager Joe Maddon said of one pitcher, adding of another, “I’ve never seen anything like this — a combination of pure stuff and results.”

In Washington, Nationals pitcher Max Scherzer discussed his season.

“I feel like all my stuff’s there,” said Scherzer, who went on to throw his second no-hitter of the year, a 17-strikeout gem against the New York Mets on Saturday night.

In Chicago, Cubs outfielder Chris Coghlan was asked about Pittsburgh Pirates pitcher Gerrit Cole.

“He’s got plus stuff,” Coghlan said. “Anytime you face an ace with that kind of stuff, it’s going to be a grind.”

Cincinnati Reds third baseman Todd Frazier spoke of Mets pitcher Matt Harvey.

“His mediocre stuff will get most people out any day of the week,” he said, adding that the Mets’ rotation featured lots of “nasty off-speed stuff.”

Mets manager Terry Collins talked about one of his pitchers, Noah Syndergaard.

“His stuff, we all know he’s got great stuff,” Collins said.

And that was just the National League. There was plenty more stuff in the American League.

Baseball considers itself the most thoughtful of games, a pastime more than a sport, written about with reverence and lyricism, in which pitching is considered more art than athleticism.

Yet the primary term used to explain the art of pitching, which often determines who wins and who loses, is an inelegant word of ill-defined mush.

Stuff.

“Stuff is a big word in baseball,” said Roger Craig, who pitched for 12 seasons in the major leagues, beginning in 1955, and coached pitchers and managed for nearly 25 more. “It’s probably used more than any word that I can think of, especially in pitching.”

Its use as a descriptor in baseball dates back more than a century. It is a word so ordinary that it avoids consideration as a cliché, hidden behind an ever-creative spectrum of modifiers: pure stuff, ace stuff, nasty stuff, hit-and-miss stuff, electric stuff, primary stuff, secondary stuff, top-rotation stuff, off-speed stuff.

Stuff can be good, great, tremendous. Some pitchers have plus stuff. Some have more.

“I don’t think his stuff was plus-plus like it normally is,” Collins said in April of Harvey.

The word flows from the lips of the smartest baseball people, unchallenged as if it made perfect sense. But ask them to define “stuff” and their stuff goes off-speed.

“That’s a good question,” said Ryan Dempster, an MLB Network analyst who won 132 games in the majors. “Stuff, to me, is the ability to throw a pitch in the strike zone and overpower a hitter, or dominate a hitter.”

John Smoltz, another MLB analyst, had enough stuff to pitch for 21 seasons and reach the Hall of Fame. He recently suggested that this year’s Mets had more stuff than the Atlanta Braves staff of Smoltz, Tom Glavine and Greg Maddux in the 1990s. That stirred an unwinnable debate fueled mostly by the word at its center.

Smoltz himself took several attempts before settling on a definition.

“Stuff is something that will make a hitter very uncomfortable,” he said. Then he amended it with less-succinct explanations.

The word is both meaningful and meaningless. There are no synonyms. Like pornography, stuff is defined mostly by example. And only pitchers have stuff. Hitters do not have stuff.

“Hitters got tools,” Dempster said. “We never say the pitchers got tools. We say the pitchers got stuff.”

Merriam-Webster has many definitions of stuff, from tangible materials (move your stuff) to ethereal knowledge (know your stuff). Its eighth definition — “spin imparted to a thrown or hit ball” — mentions baseball.

“The movement of a baseball pitch out of its apparent line of flight; the liveliness of a pitch,” the definition reads.

But that is too precise for baseball’s cloudy vernacular. Stuff can describe a collection of pitches, how well those pitches are thrown on a particular day, and how well they fool hitters.

“It can mean a lot of things,” Craig said. “If you’ve got a guy like Tom Seaver, you say he’s got good stuff. But if you’ve got a guy with average stuff, you might say that he has good stuff today. It depends on the pitcher and what he usually does.”

The conversation went in circles. Craig took a breath.

“It’s confusing,” he said. “The average person wouldn’t understand.”

It is not for having never heard it. Stuff has been part of baseball terminology since sometime shortly after the game’s origin. In 1896, The New York Times wrote about the bleak prospects of Yale’s team, writing of one infielder, “It is thought that he has some genuine baseball stuff in him, though it is in an immature state, and will require a great deal of coaching to develop.”

By the turn of the century, the word started applying specifically to pitchers. One creative Times reporter in 1908 gave voice to New York Giants manager John McGraw in an imaginary conversation with pitcher Doc Crandall.

“They’ll never get to that stuff of yours, and even if they did, we can hit anything they can bring out,” McGraw probably did not say.

In early 1911, in an article written for The Times about the best pitchers of the era, Boston manager Fred Tenney provided a rare definition when describing Christy Mathewson. “I consider him the greatest pitcher that ever was in the game,” Tenney wrote. “He has more ‘stuff’ than any other.”

Everyone from Ted Williams to Bob Feller used the word to explain pitchers. Connotations shifted slightly over the years. In a 1980 New York Times Magazine article about pitching, writer Tony Scherman said that “stuff” referred to power, not spin.

“The power pitcher relies on velocity, also known as ‘good stuff,’” he wrote.

(By then, “stuff” was in its etymological heyday in popular culture. George Carlin riffed on stuff — “That’s what your house is, a place to keep your stuff while you go out and get more stuff,” he said. Nabisco released the curiously spelled “Double Stuf” Oreo cookie. And, in 1985, a horror-movie spoof called “The Stuff” was released, about a substance that oozes from the ground, is tasty enough to cause a sensation and eats our minds. It only sounds like a baseball movie.)

But the term has settled in, like a pitcher finding his stuff, beyond measures of speed and spin to some intangible quality of command and confidence.

Collins, the Mets’ manager, may use it most, and with admirable range. He has started sentences with the term “stuff-wise.” He has talked about “dead-arm stuff” and “pure stuff,” and everything in between. “I saw outstanding stuff,” Collins said of Harvey in June. “Tonight he commanded his stuff.”

As the playoffs begin, plenty of experts will forecast that the pitching staffs with the best stuff are likeliest to win. That can be hard to predict.

Perhaps that is why, in early September, as the Mets and their strong pitching staff were positioned for a playoff run, general manager Sandy Alderson warned of overconfidence.

“Stuff happens,” he said. Which is something everyone understands.