====== Stack ======

**What it is:** A collection of AWS resources created and managed as a single unit by CloudFormation.

**What it’s for:**
  * Manage resources together (create/update/delete as a unit).
  * Keep environments consistent (dev/stage/prod).

**Key ideas:**
  * Stack updates apply changes based on template differences.
  * Failed updates can roll back automatically.

**Hard words:**
  * *collection* /kəˈlekʃn/: tập hợp
  * *unit* /ˈjuːnɪt/: đơn vị