I do not understand part $(2)$ of Proposition-Definition 1.2 on page $64$ of Hartshorne's Algebraic Geometry:
The original texts are:
'Given a presheaf $F$ ... $F^{+}(U)$ is the set of functions $s$ from $U$ to the union $\cup F_{P}$ ... $(2)$ for each $P\in U$, there is a neighborhood $V$ of $P$, contained in $U$, and an element $t\in F(V)$, such that for all $Q\in V$, the germ $t_{Q}$ of $t$ at $Q$ is equal to $s(Q)$.'
What I understand so far:
1) I know the definition of a presheaf and a sheaf.
2) I understand stalk $F_{P}$ at a point $P$ as a direct limit.
What I don't understand is specifically:
1) What does the germ $t_{Q}$ of $t$ at $Q$ mean?
$s(Q)$ is an element of stalk $F_{Q}$ which would force $t_{Q}\in F_{Q}$ but what is $t_{Q}$?