[Bamboo Knowledge Base]
Stages group (or 'map') jobs to individual steps within a plan's build process. For example, you may have an overall plan build process that comprises a compilation step, followed by several test steps, followed by a deployment step. You can create separate Bamboo stages to represent each of these steps.
A stage:
Each new plan created in Bamboo contains at least one stage (for the default job) and is known as the 'Default Stage'. Stages can only be configured by Bamboo administrators.