What is the difference between 3-tier architecture and Layered architecture?

 Tiers are the physically separate components of the same system. On the other hand, layers refer to the internal architecture of your component. Layers are a way of organizing your code   like    Presentation, Business and Data layers. Three-tier refers to the actual n system components of your application. For ex: Suppose you create a web application, its components include your application server where it is being hosted, the database being used with it, on another server and the user machine who access the application, forms the third component. These are referred to as the3 tiers of your application