Route::get('/products/{id}', function ($id) { // logic for retrieving product with given id })->where('id', '[0-9]+');In this example, we are defining a route that accepts a product ID as a parameter in the URL. We are also using the `where` method to specify that the `id` parameter must be a number. The `Route` class is part of the Laravel framework, which is a popular PHP web development framework. The code above is an example of how to define a route using the Laravel framework's router.