What do you mean by design patterns?

Design patterns are divided into three fundamental groups:

– Design patterns are formalized best practices that the programmer can use to solve common problems when designing an application or system . Design Patterns establishes solutions to common problems which helps to keep code maintainable, extensible and loosely coupled.

In software engineering, a software design pattern is a general, reusable solution to a commonly occurring problem within a given context in software design . It is not a finished design that can be transformed directly into source or machine code.

In software development, a pattern (or design pattern) is a written document that describes a general solution to a design problem that recurs repeatedly in many projects . Software designers adapt the pattern solution to their specific project.