NaN

NaN is a JavaScript term, not specifically a React JS term, but it is used within React JS as it is part of JavaScript. NaN stands for Not a Number. It is a special type of value that indicates the value cannot be represented as a valid number. It is usually the result of a mathematical operation that fails to produce a well-defined number.

Here's an example:

```js
console.log(0 / 0); // outputs NaN
```

The division of zero by zero is undefined, thus JavaScript returns NaN.

In this example within a React component:

```jsx
class MyComponent extends React.Component {
render() {
let result = 0 / 0; // result is NaN
return <div>{result}</div>;
}
}
```

In this scenario, the component tries to divide 0 by 0, which results in NaN, and this is what will be rendered in the div. However, it's worth noting that `NaN !== NaN` is a quirk of JavaScript and it would return true. The correct way to check for NaN in your code is by using the built-in JavaScript function `isNaN()` or `Number.isNaN()`.