CodePipeline

Pipeline is what encompasses all components

Stage represents a step in the pipeline. The most common steps would be Source > Build > Deploy. You can add many stages, so use your creativity

Action Groups groups several actions together

Action does something e.g. pull source code, build and run tests, deploy to production, invoke a lambda, invoke a CloudFormation template.

Artifact is a zip containing files outputted by an action and stored in s3. An artifact can be passed to any future actions and some actions required to input an artifact can be optional input for an artifact

Stage Transition are links to the next pipeline stage

Actions

These are all the possible Actions. Actions are not restricted to specific stages. E.g. you cna you Deploy Actions in a Build Stage. Pipelines are only limited by your creativity. You can create custom actions if you need functionality beyond this list.