Definition:In-Degree

Definition
Let $G = \left({V, E}\right)$ be a digraph.

Let $v \in V$ be a vertex of $G$.

The in-degree of $v$ in $G$ is the number of arcs which are incident to $v$.

It is denoted $\operatorname{indeg}_G \left({v}\right)$, or just $\operatorname{indeg} \left({v}\right)$ if it is clear from the context which graph is being referred to.

Also see

 * Definition:Out-Degree


 * Definition:Degree (Vertex) in the context of undirected graphs