It’s 2018, and the U.S. Food and Drug Administration is trying to figure out what milk is.

In a policy summit on July 17, FDA commissioner Scott Gottlieb expressed frustration that the term “milk” is used willy-nilly in the labeling of nondairy beverages such as soy milk, oat milk and almond milk. “An almond doesn’t lactate,” he said.

Gottlieb’s stance isn’t rooted in semantics. He argues that putting dairy and nondairy milks under the same umbrella dupes consumers into thinking the two are nutritional equals, which, according to him, could have potentially dire consequences such as rickets in toddlers. “Such public health concerns are one of the reasons why we’re prioritizing this effort to take a closer look at the standards of identity for dairy products,” he wrote in a press release .

Of course, a more cynical read of the situation posits that Big Dairy is leaning on the FDA to discredit plant milks, the industry’s biggest competition, as a viable substitute for cow’s milk.

Be that as it may, the FDA’s position on what’s milk and what’s not—and what is ultimately at stake—has nutritionists, food historians and even lexicographers scratching their heads. Marion Nestle, professor emerita of nutrition, food studies, and public health at New York University, explains there’s a problem in Gottlieb’s premise. “I’m not aware of any evidence for significant nutrient deficiencies in the American diet,” she says. “Milk is not essential after infancy, and people who choose not to drink it can get those nutrients from other sources quite easily.”

Linguistically speaking, using “milk” to refer to the “the white juice of certain plants” (the second definition of milk in the Oxford American Dictionary) has a history that dates back centuries. The Latin root word of lettuce is lact , as in lactate, for its milky juice, which indicates that even the Romans had a fluid definition for milk.

Ken Albala, professor of history at University of the Pacific and host of the podcast Food: A Cultural Culinary History , says that almond milk “shows up in pretty much every medieval cookbook.” Almonds, which originate in the Middle East, reached southern Europe with the Moors around the 8th century, and their milk—yes, medieval Europeans called it milk in their various languages and dialects—quickly became all the rage among aristocrats as far afield as Iceland.

At this time, most European Christians still adhered to an edict from the Didache , an early Christian treatise, that forbade consuming animal products on Wednesdays and Fridays. “Almond milk became a nutritious stand-in,” Albala says. As the Church and its followers became more lackadaisical on the issue of fasting, almond milk went out of vogue in Europe, but it can still be found in dishes like ajo blanco , Spain’s white gazpacho thickened with bitter almonds. Its use was phased out blancmange , then a savory entrée of chicken pounded with almond milk and rosewater that’s better-known today as a panna cotta-esque dessert.

Around the same time that almond milk’s popularity was peaking in Europe, a precursor to soy milk called doufujian was becoming popular in 14th-century China. The protein-packed liquid was ladled hot into bowls for breakfast and served alongside crisp, savory doughnuts. Dairy products “were never really to catch on in China except in the days of the Tang as a passing fashion,” culinary historian Reay Tannahill reflected in the 1973 book, Food in History . “The people of China, like other non-pastoral societies, had their own perfectly satisfactory alternatives to milk products.”

Nondairy milks abounded in many other cultures across the globe: Coconut milk, made by soaking grated coconut in water, has been the backbone of Southeast Asian, African and Indian cuisines for centuries if not millennia. (Some languages, like Thai, Filipino and Swahili, have a separate, specific word for coconut milk, while others, like Farsi, Hindi and Punjabi, use “milk” to describe both animal- and plant-based secretions.)

To this day, tiger nuts, a Berber import to Spain from North Africa, are still the main ingredient in horchata , Valencia’s signature summer beverage. Hazelnut and pistachio milks featured occasionally in medieval cookbooks as well, though less is known about where these originated.

Drinking fresh milk—plant-based or otherwise—as a beverage remained uncommon until the 19th century. “There was no cow’s milk trade until modern times,” says Anne Mendelson, food journalist and author of the 2008 book, Milk: The Surprising Story of Milk Through the Ages . “In places where people could digest lactose, animal milk was occasionally drunk on its own, but it was more commonly fermented, which made it more digestible and less hospitable to harmful pathogens.”

Cow milk’s perishability plays a major role in why more people weren’t drinking the stuff; producing it on an industrial scale is a costly and complex enterprise. The modern dairy industry necessitates live animals, expensive machinery and refrigerated trucks, a financial model that is proving untenable. Small dairies, once common are, in turn, dropping like flies.

Demand is also an issue; according to a 2016 report by market research firm Mintel, milk sales have been falling and will continue to fall through at least 2020. “The dairy industry is extremely troubled right now,” says Mendelson, who explains that Big Dairy in the United States has only managed to stay afloat because of the subsidies it receives from the federal government .

Plant milks, unsurprisingly, are an existential threat to the dairy industry. According to another Mintel report , nondairy milk sales grew 61 percent between 2012 and 2017, a statistic that likely made major dairy producers curdle.

“We have an administration that’s very sensitive to corporate interests,” says Nestle of the new leadership of the FDA. “If I were running a major dairy operation and saw a way to paint my competition in a bad light, I’d move very quickly right now.”

But if coming for plant-milk nomenclature is the best the dairy industry’s got, the Rice Dreams and Vita Cocos of the world can probably exhale. The FDA may succeed in banishing “milk” from nondairy milk labels, but it’s unlikely to affect consumer habits in a meaningful way. If anything, it could be a boon to the plant-milk industry like the “vegan mayo wars” of 2014 ultimately were to eggless spreads.

Unless the FDA can prove conclusively that nut milks cause rickets, for instance, consumers are poised to continue buying the nondairy milks they’ve been consuming for centuries. Says food historian Albala about the recent dairy nomenclature war, “I’m putting my money on nut milks.”