# DSE Graph Terminology

This terminology is specific to DSE Graph.

A collection of unordered lists used to represent a finite graph. Each list describes the set of neighbors of a vertex in the graph.

A vertex directly attached to another vertex by an edge.

directed graph

A set of vertices and a set of arcs (ordered pairs of vertices). In DSE Graph, the terminology "arcs" is not used, and edges are directional.

edge

A connection between vertices. Edges can be unordered (no directional orientation) or ordered (directional). An edge can also be described as an object that has a vertex at its tail and head.

element

An element is a vertex, edge, or property.

global index

An index structure over the entire graph.

graph

A collection of vertices and edges.

graph degree

The largest vertex degree of the graph.

graph partitioning

A process that consists of dividing a graph into components, such that the components are of about the same size and there are few connections between the components.

graph traversal

An algorithmic walk across the elements of a graph according to the referential structure explicit within the graph data structure.

incident edge

An edge incident to a particular vertex, meaning that the edge and vertex touch.

index

An index is a data structure that allows for the fast retrieval of elements by a particular key-value pair.

meta-property

A property that describes some attribute of another property.

partitioned vertex

Used for vertices that have a very large number of edges, a partitioned vertex consists of a portion of a vertex’s data that results from dividing the vertex into smaller components for graph database storage.

Experimental

property

A key-value pair that describes some attribute of either a vertex or an edge. Property key is used to describe the key in the key-value pair. All properties are global in DSE Graph, meaning that a property can be used for any vertices. For example, "name" can be used for all vertices in a graph.

traversal source

A domain specific language (DSL) that specifies the traversal methods used by a traversal.

undirected graph

A set of vertices and a set of edges (unordered pairs of vertices).

vertex-centric index

A local index structure built per vertex.

vertex

A vertex is the fundamental unit of which graphs are formed. A vertex can also be described as an object that has incoming and outgoing edges.

vertex degree

The number of edges incident to a vertex.