Azure resource that deploys and manages a set of resources defined in a Bicep or ARM template as a single unit. It keeps track of the resources it manages, can prevent them from being modified or deleted outside the stack (deny settings), and deletes or detaches them when they are no longer part of it. It is the recommended replacement for Azure Blueprints, retired in July 2026.
In AZ-305 it appears in governance and landing zone design: repeatably deploying Azure Policy assignments, RBAC roles and shared resources (for example a Log Analytics workspace) to every new subscription. It is created at a resource group, subscription or management group scope. Question: package policies, roles and resources as a unit and protect them against changes → Deployment Stacks.
Azure Deployment Stacks is a concept that can show up on the exam. Check the full guide to see it in context.