> \[!NOTE\] **rune** /ruːn/ *noun*
> 
> A letter or mark used as a mystical or magic symbol.

Runes are symbols that you use in `.svelte` and `.svelte.js`/`.svelte.ts` files to control the Svelte compiler. If you think of Svelte as a language, runes are part of the syntax — they are *keywords*.

Runes have a `$` prefix and look like functions:

```js
let message = $state('hello');
```

They differ from normal JavaScript functions in important ways, however:

*   You don't need to import them — they are part of the language
*   They're not values — you can't assign them to a variable or pass them as arguments to a function
*   Just like JavaScript keywords, they are only valid in certain positions (the compiler will help you if you put them in the wrong place)

> \[!LEGACY\] Runes didn't exist prior to Svelte 5.