DAG stands for Directed Acyclic Graph.
A DAG is a graph where information must travel along with a finite set of nodes connected by vertices. There is no particular start or node and also no way for data to travel through the graph in a loop that circles back to the starting point.
It’s a popular way of building data pipelines in tools like Apache Airflow, dagster, Prefect. It clearly defines the data lineage. As well, it’s made for a functional approach where you have the idempotency to restart pipelines without side-effects.
