# Definition:Circuit (Graph Theory)

## Definition

A circuit is a closed trail with at least one edge.

### Subgraph

The set of vertices and edges which go to make up a circuit form a subgraph.

This subgraph itself is also referred to as a circuit.

## Also defined as

Some sources specifically state that a circuit must have at least $3$ edges.

However, as defined on $\mathsf{Pr} \infty \mathsf{fWiki}$, this criterion emerges as a consequence of the definition.

## Also known as

Some sources refer to this as a closed trail.