Terraform is an open-source infrastructure-as-code tool that allows you to define, provision, and manage infrastructure across multiple cloud providers. On Debian 11, it can be easily installed using the official HashiCorp repository. Terraform uses HCL (HashiCorp Configuration Language) to write configuration files for automating infrastructure tasks like creating, updating, and destroying resources. It supports powerful features like state management, variables, and outputs to maintain infrastructure consistency. Ideal for scalable, repeatable cloud infrastructure management, Terraform streamlines cloud provisioning and reduces manual errors.