Description: The Function ARN in AWS CloudFormation is a unique identifier used to refer to a specific function within the Amazon Web Services infrastructure. ARN, which stands for Amazon Resource Name, is a standard format that allows users to accurately and uniquely identify resources in the AWS cloud. In the context of CloudFormation, the Function ARN is crucial for resource management and automation, as it enables developers and solution architects to refer to Lambda functions and other services in a consistent and unambiguous manner. This identifier includes information about the region, the AWS account, and the resource type, facilitating integration and interoperability between different cloud services. The ability to use Function ARNs in CloudFormation templates allows users to define, create, and manage resources efficiently, ensuring that configurations are reproducible and scalable. Additionally, the use of ARNs helps maintain security and access control, as specific policies can be applied to uniquely identified resources.