A directed acyclic graph (DAG) is a type of data structure where no cycles (loops) are permitted and nodes are connected by directed edges that point in a certain direction from one node to another. Put more simply, it's a graph with unbroken information flows in a single direction.

Here are the key characteristics of a Directed Acyclic Graph (DAG):

1. Directed Edges: In a DAG, every edge has a direction that represents the information flow or interdependence between nodes. An edge, for instance, connecting nodes A and B indicates that node A depends on or impacts node B.

2. Acyclic Nature: There are no loops or cycles in DAGs. This implies that you cannot follow a series of edges through a DAG and arrive back at the initial node. This feature is essential for many applications, such task scheduling and dependency resolution.

3. Nodes: In a DAG, entities or items are represented by nodes, and relationships or dependencies between these entities are shown by edges. Depending on the particular use case of the DAG, nodes may be linked with values or characteristics.

Directed Acyclic Graphs find applications in various fields, including:

1. Dependency Resolution: Software package managers frequently employ DAGs to illustrate package dependencies. Packages are represented by each node, while dependencies between packages are shown by edges.

2. Task Scheduling: DAGs are used to express dependencies between jobs or tasks in task scheduling software. A job is represented by each node, and the interdependence or order between tasks is shown by the edges.

3. Blockchain Technology: A DAG-based structure is used by certain blockchain systems, such IOTA and Nano, in place of a conventional blockchain. Each transaction in these systems is represented as a node in the DAG, and there is no strict block ordering required; transactions can be added to the DAG asynchronously.

All things considered, directed acyclic graphs are adaptable data structures that are used in many different applications where it is required to describe directed links without cycles.