  This paper presents a fanctor $S$ from the category of groupoids to the
category of semigroups. Indeed, a monoid $S_G$ with a right zero element is
related to a topological groupoid $G$. The monoid $S_G$ is a subset of
$C(G,G)$, the set of all continuous functions from $G$ to $G$, and with the
compact- open topology inherited from C(G,G) is a left topological monoid. The
group of units of $S_G$, which is denoted by $H(1)$, is isomorphic to a
subgroup of the group of all bijection map from $G$ to $G$ under composition of
functions. Moreover, it is proved that $H(1)$ is embedded in the group of all
invertible linear operators on $C(G)$, the set of all complex continuous
function on $G$.
