A design pattern is defined as the re-usable form of a solution to a design problem. With a design pattern, you can document a solution to a design problem. Design patterns were introduced by the architect Christopher Alexander and have been adapted for various other disciplines and are very popular among developers, as they provide solutions to general problems that software developers face. It provides a template to solve common problems while designing a system or an application.
Design patterns act as a common language between developers so that each developer easily understands the concept while working with common problems.