DAGs - KeynesYouDigIt/Knowledge GitHub Wiki
In mathematics, particularly graph theory, and computer science, a Directed Acyclic Graph is a directed graph with no directed cycles. That is, it consists of nodes and edges (also called arcs), with each edge directed from one node to another, such that following those directions will never form a loop. A directed graph is a DAG if and only if it can be topologically ordered, by arranging the nodes as a linear ordering that is consistent with all edge directions. (mostly copied from wikipedia).
In Data Engineering, DAGs refer to a set of scripts that run in an Acyclic manner, usually doing some data extraction, loading, and/or transformation.