[Thomas]

This is a good link -
https://developer.salesforce.com/docs/atlas.en-us.216.0.pages.meta/pages/pages_intro.htm

Salesforce has created a comprehensive platform for building on-demand applications. Like other sophisticated application development platforms, the Lightning platform offers separate tools for defining:

(M) The structure of the data—that is, the data model

(V) The layouts that specify how that data should be displayed—that is, the user interface

(C) The rules that detail how that data can be manipulated—that is, the business logic

Splitting up application development tools based on whether they affect the data model, business logic, or user interface is also known as the Model-View-Controller (MVC) application development pattern—the Model is the data model, the View is the user interface, and the Controller is the business logic.