In October 2025, members of the European Parliament voted in favour of a bill to reserve terms such as “burger” and “sausage” for meat products. If this bill is approved by most EU member states, products made from meat alternatives or vegetables will no longer be allowed to have “burger” on their packaging.

This bill would change the words on the packaging, but it is not enough to change the words that people use in their everyday lives. A push to change the meaning of a word from a government body is unlikely to be successful, linguistically speaking, because of how the human brain processes and stores the meaning of words.

People often think that the meaning of a given word is a single, unchanging definition, much like you would expect to find in a dictionary. However, the linguistic part of the brain that stores words and their meanings is actually a lot more dynamic – and a lot more vague – than that.

Our understanding of meaning is a lot more “I’ll know it when I see it”. Consider the word “milk”. Attached to that word are a number of qualities that you, personally, find relevant to its meaning. These qualities might include its source (from a cow, a pint carton from the supermarket), its appearance (white, liquid) and its function (a drink, a component in coffee or tea, poured over cereal, as an ingredient in baking, or processed into cheese/yoghurt/cream).

• ** Read more: Plant-based foods: businesses alone shouldn’t decide what we call a veggie burger ** *

It is these qualities that are stored in the brain under the category “milk”. These qualities, or meanings, are continuously edited, upgraded and discarded over time as we gain new information. By this process, the brain learns how to categorise new experiences or unusual examples, such as chocolate-flavoured milk.

Plant-based alternatives have many of the same qualities as their dairy equivalent. Garna Zarina/Shutterstock

Now consider a dairy alternative, such as one made from oat or soya. This plant-based product has many of the same qualities as its dairy equivalent. The milk alternatives fit the appearance and function of milk, and so they are stored under the category “milk” in the brain.

If oat milk is something you drink regularly, then your meanings will update to reflect this: oat milk will become the prototypical “milk” in your brain. Even if oat milk is not a common occurrence in your everyday life, your brain will likely store it under the linguistic category of “milk”, albeit as a fringe example of milk.

When is a burger not a burger?

Now let us consider the meanings associated with a word like “burger”. Its source (beef, turkey, chicken, pork, bean, falafel, meat alternatives), its appearance (a processed disc patty, presented in a bun) and its function (a patty placed in a bun, usually with some accompanying salad or sauces).

There aren’t any non-burger products that have been processed into the prototypical burger-shaped disc. Tatjana Baibakova/Shutterstock

The first thing you might notice is how many options there are for the source of the burger. Most of these sources are quite common and well-known. Even if you yourself have a strong preference for beef burgers, you probably wouldn’t consider a chicken burger an unusual example of a burger.

In other words, our linguistic category of “burger” allows a lot more flexibility and a wider range of sources than “milk”. On the other hand, the shape of the burger (a processed disc patty) and its function (between two buns) are both very important and more restrictive qualities of a burger.

This is in part because there aren’t any non-burger products that have been processed into the prototypical burger-shaped disc. Similarly, there aren’t any sausage-shaped products that aren’t sausages. The shape of the burger is reinforced in our mental linguistic definitions every time we see a burger, and is never undermined by seeing a non-burger patty. This is why we feel very strongly that the very essence of a burger is tied to its function and its shape.

The meaning of the word “burger” doesn’t come from the dictionary definition, or from being told what a burger is by a government. In fact, there isn’t one single meaning for “burger”.

Instead, in the linguistic database in our brain, we have a collection of meanings that we associate with burgers. This linguistic ability allows us to confidently categorise burgers from non-burgers, even if it is, ironically, hard for us to put into words. What is a burger? I’ll know it when I see it.

Don’t have time to read about climate change as much as you’d like? Get a weekly roundup in your inbox instead. Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. Join the 45,000+ readers who’ve subscribed so far.