Docker Compose is a tool that lets you run more than one container at a time, with links / dependencies between them.
This is often called "Orchestration" because that's a lovely word isn't it.
Docker Compose's orchestra of containers are defined in a docker compose YAML file.
It is particularly well suited for local development and testing, though it can also be used in production.
In production, alternative "Container Orchestration" techniques such as Kubernetes are more widely used.