In Svelte, a **slot** is a placeholder inside a component where you can insert content from the parent component. A **default slot** is the most common type of slot and is used when you want to pass children content without naming the slot.
To define a default slot, you use the `<slot></slot>` element inside a child component. This tells Svelte where the parent-provided content should be rendered.
When using the component, you can place any content between its opening and closing tags. That content will be inserted where the `<slot>` is defined.
You can also add fallback content inside a slot. This fallback will be displayed **only if no content is passed** from the parent.