What is C/SIDE and C/AL

Stands for: 

• C/SIDE – Client/Server Integrated Development Environment
• C/AL –  Client/Server Application Language

Description.
C/AL is the programming language that used within the development environment for Microsoft Dynamics NAV, and the development environment is called as C/SIDE. C/AL is a database specific programming language and it primarily used to retrieve, insert, and modify the records in the dynamics NAV Database. C/AL is extended from the PASCAL language and original C/AL compiler was written by Michael Nielsen.

When changing the NAV application according to the requirements, developer does not change the executable s (.exe files), but the “Objects”. 
Dynamics NAV database contain definitions of the each object and each object contain business logic to run the ERP application.