Explain what is meant by 'design pattern' and its role in software development.

A design pattern is a time-tested solution to a common design problem in programming. It describes how to structure code and interactions between components to solve a specific issue, without being tied to a particular implementation.

The role of design patterns:

• Improve code quality and readability.
• Facilitate maintenance and extension of software.
• Reduce the likelihood of errors by using proven approaches.
• Enhance communication among developers, as patterns have widely accepted names and descriptions.

Example: The Singleton pattern guarantees that a class has only one instance and provides a global point of access to it.

public class Singleton
{
    private static Singleton _instance;
    private Singleton() { }
    public static Singleton Instance
    {
        get
        {
            if (_instance == null)
                _instance = new Singleton();
            return _instance;
        }
    }
}

Using patterns helps create more robust and understandable architectures.