The AWS CDK (Cloud Development Kit) is an open-source software development framework that allows developers to define cloud infrastructure using familiar programming languages like TypeScript, JavaScript, Python, Java, and C#. It simplifies the process of creating and managing cloud resources on the Amazon Web Services platform by enabling users to write code that represents their infrastructure. With the AWS CDK, developers can leverage high-level constructs called "L2 constructs" that encapsulate best practices and simplify resource management. This approach allows for easier maintenance and scalability of applications, making it a powerful tool for building cloud-native applications efficiently.