A reusable set of Terraform resources grouped in a directory. The root module is the main working directory. Child modules are called from the root and can come from local sources, the Terraform Registry, or Git repositories.
In Terraform Associate, modules are the way to reuse code. Input variables (variables.tf) and outputs (outputs.tf) define the module's interface. Question: how do you reuse the same VPC configuration across multiple environments? With a module.
Terraform Module is a concept that can show up on the exam. Check the full guide to see it in context.