Definition - What does Multi-Tier Application mean?
A multi-tier application is any application developed and distributed among more than one layer. It logically separates the different application-specific, operational layers. The number of layers varies by business and application requirements, but three-tier is the most commonly used architecture.
Any application that depends on or uses a middleware application is known as a multi-tier application.
A multi-tier application is also known as a multitiered application or n-tier application.
Techopedia explains Multi-Tier Application
A multi-tier application is used to divide an enterprise application into two or more components that may be separately developed and executed.
In general, the tiers in a multi-tier application include the following:
Presentation tier: Provides basic user interface and application access services
Application processing tier: Possesses the core business or application logic
Data access tier: Provides the mechanism used to access and process data
Data tier: Holds and manages data that is at rest This division allows each component/tier to be separately developed, tested, executed and reused.