Explain Docker Compose and provide a practical example.

Docker Compose is a tool for defining and running multi-container applications using YAML files. Key features: 1) Service definition, 2) Network configuration, 3) Volume management, 4) Environment variables, 5) Dependencies between services. Example docker-compose.yml includes web service with build context, ports 3000:3000, depends on db, and db service with postgres:13 image, environment variables, and volumes. Commands: docker-compose up -d (Start services), docker-compose down (Stop and remove), docker-compose logs (View logs).