This article explains search scopes in SharePoint 2013 using result sources.
Introduction
In SharePoint 2013 Search Scopes have become Result Sources, the "scopes" are replaced by a new thing called “Result Sources”. By replaced I mean you cannot create or use the Search Scopes anymore. No more displaying a custom Search Scope in a drop-down next to the search box. There are only two system Search Scopes, All Sites and People, will be available in the search results page. The method of customizing the display of the search results in a SharePoint 2013 search has improved drastically from SharePoint 2010.What happened to Search Scopes: They are depreciated or rather are integrated into Federated Search to create an advanced version of these scopes.What are Result Sources: Result Sources are actually the combination of Federated Search and Search Scopes. In SharePoint 2013 you can create a new Result Source and specify the “Protocol” (to search Local SharePoint or a Remote SharePoint farm and so on) and can specify the “Query Transformation”.
Procedure:
Getting Started with Managed Metadata Service in SharePoint 2010