When the first-ever Pearl Diver Punch emerged from a discreet bar at Los Angeles’ Don the Beachcomber in the 1930s it signaled a dramatic shift. The drink, festooned with a geranium leaf and edible flowers and served in a bespoke glass, was the antithesis of the spartan three-ingredients formulas—Manhattan, Martini, Old-Fashioned—that had defined the bar world’s status quo for the last half-century. It belonged to an entirely new category of cocktail.

Today we call it tiki, but it wasn’t always so. “Back in the day, during the Golden Age of what we now call tiki drinks, they were never called that,” explains Jeff “Beachbum” Berry, the genre’s leading historiographer. (It was only after the drinks had faded from mainstream phenomenon to cultural artifact that the name emerged, borrowing from the central motif of the genre: tiki totems.) During their midcentury heyday, what we now refer to as tiki drinks were known interchangeably as exotic cocktails, tropical cocktails, Polynesian drinks or, in Don the Beachcomber’s parlance, “rhum rhapsodies.”

It was, in part, the very drama of these eye-catching drinks—the Shark’s Tooth, Missionary’s Downfall, the Zombie—that allowed the specifics of the genre to evade codification for so long. The formulas themselves, with their complex blends of rums and unusual modifiers like falernum and orgeat, were ruled by a certain behind-the-scenes rigorousness. But from the outside, the imprecise notion that “you know it when you see it” has long dictated the limits (or lack thereof) of tiki. “When you start calling something a tiki drink, now you have to define that,” says Berry, “but nobody did define that right when the drinks were being created.”

Tiki began as a contrived fantasy borne from the mind of a single individual: Don the Beachcomber. It didn’t take long for imitators to crop up, broadening the fantasy world to include an even wider array of drinks and décor in cities across the country. Not unlike today’s Star Wars or Marvel franchises, the rich source material of Don the Beachcomber’s original vision has allowed the genre to continue evolving, bound together less by hard-and-fast rules than by a broader core identity. To try and retroactively apply constrictions to the genre proves challenging because, as Berry puts it, “you’re creating parameters that never were for a category that never was.”

But there’s a reason—beyond the human need to label, sort and categorize—that we continue to quibble over the meaning and parameters of tiki; it’s the same reason that the library of volumes dedicated to the topic grows larger by the day, and new bars devoted to its legacy are on the rise: There’s something singular about tiki drinks—something that gets lost when tossed under the umbrella term “tropical” or the notion that “you know it when you see it.”

So what is a tiki drink, exactly?

“It all comes down to the punch formula,” says Berry, referencing the classic Planter’s Punch, a West Indies staple since the colonial era, the components of which are immortalized in a well-trod-out rhyme: one of sour, two of sweet, three of strong and four of weak. Tiki takes this baseline recipe and fractures each requisite component into multiples of each. It is, as Berry concludes, “a Caribbean drink squared, or cubed.”

Where a typical punch recipe might call for lime as the sole sour element, tiki will call for lime and grapefruit, or even lime, grapefruit and passionfruit. For the sweet element, in place of just simple syrup, honey or maple syrup might also make an appearance. But perhaps most significant is the amplification of the “strong” component. Never before in the history of the cocktail had a mixed drink doubled down on the base spirit by splitting it into multiple rums, or even multiple spirits, like rum, Cognac and gin in the case of Trader Vic’s Fog Cutter. Doing so would become a hallmark of the style.

“It’s a baroque Planter’s Punch,” says Martin Cate, owner of San Francisco tiki mecca, Smuggler’s Cove. “Tiki has a clear definition of what it’s supposed to be,” he continues, “it has to have sour, sweet, spirit working in equal and interesting ways, complex ways, and it has to have—in my take—some kind of spice component to it.”

Indeed, spice is a key component of many tiki recipes, particularly those drawn from Don the Beachcomber’s library of work. (His proprietary syrup, known as Donn’s Mix, was a central component to many of his recipes and consisted of grapefruit juice and cinnamon syrup.) But can tiki’s entire identity rest on such a minute detail as a dusting of nutmeg or cinnamon atop a multi-rum base?

Yes and no. But a more concrete answer begins with explaining why, for instance, a Piña Colada is categorically not a tiki drink. With its pineapple wedge and umbrella it certainly looks the part. At its core, however, its rum-pineapple-coconut construction lacks the requisite sour element of a Planters Punch (and, in fact, many Caribbean classics like the Daiquiri and the Mojito). Created in the 1950s at a resort in San Juan, the Piña Colada slots better into a category known as “resort drinks” or “boat drinks,” which, by the 1970s, had subsumed the title “tropical.”

This conflation of terms undermined another key point of differentiation between tropical and tiki—namely, that the latter sparked a robust culture that went well beyond a genre of cocktails, to span architecture, decor, sculpture, glassware, cuisine and apparel. At one point the difference between a tropical drink and a tiki drink was defined by where it was served.

Today, however, the two find themselves once again intertwined, this time under the elevated umbrella of “craft cocktails.” The same forces that rescued both the stalwarts of the Golden Age of cocktails and the maligned disco drinks of the 1970s have worked their magic on their tropical brethren. What happens, then, when the Piña Colada borrows from the tiki textbook and adopts a multi-rum base as it has in so many modern variations? Served at a tiki bar—as it often is—it starts to look a lot like a tiki drink.

Tiki’s very adaptability has allowed it to not only imprint on tropical drinks, but other non-tiki drinks as well. Which is why, at bars like Chicago’s Lost Lake or New Orleans’ Latitude 29 you’ll find a Painkiller—essentially a Piña Colada with orange juice—or a Daiquiri comfortably alongside updated versions of the Mai Tai or Fog Cutter. It’s made the line between tiki and non-tiki ever harder to distinguish, prompting the question of whether there’s even really a need for one.

We can agree to some of tiki’s essential ingredients, formulas and techniques, but the patterns that repeat are just as important to tiki as those that don’t. Perhaps the most critical facet of tiki, like any great fantasy genre, is its adherence only to the limits of our own imagination.