What does Action mean in play framework (Scala)?

Question

I am new to Play Framework and was trying to understand SimpleRouter class. In the Play documentation, I see a simple example as:

val router = Router.from {
  case GET(p"/hello/$to") =>
    Action {
      Results.Ok(s"Hello $to")
    }
}

But I am not sure what is Action and what is its significance? I see it heavily used in all other routing methods as well. Here's the link to the documentation: https://www.playframework.com/documentation/2.8.x/ScalaSirdRouter

My reference code:

import play.api.mvc._
import play.api.routing.Router._
import play.api.routing._
import play.api.routing.sird._


class CacheRouter extends SimpleRouter {



  override def routes: Routes = {
    case GET(p"/") =>
      Action {
        Results.Ok(s"Hello")
      }

//    case POST(p"/") =>
//      controller.process
//
//    case GET(p"/$id") =>
//      controller.show(id)
  }

}