I am using the align command to align equations :
\begin{align*}
\psi \colon & SU(2)\otimes SU(2) \otimes SU(2) \to \mathbb{C}\\
&(U_{l_1} \otimes U_{l_2} \otimes U_{l_3}) \mapsto \psi(U_{l_1} \otimes U_{l_2} \otimes U_{l_3}).
\end{align*}
As I understand it, the "&" tells to latex where the object need to be vertically aligned.
But does & mean something in general in latex ? Or is it a command that has always different significations ?