\&The \& symbol in LaTeX is used to align columns in tabular environments. It acts as a column separator in tables and arrays, allowing for the organization of data into neat columns.
A simple table with two columns separated by \&.
\begin{tabular}{c|c}
A & B \\
1 & 2 \\
3 & 4 \\
\end{tabular}An array with two columns, using \& to separate the elements.
\begin{array}{cc}
x_1 & y_1 \\
x_2 & y_2 \\
\end{array}Aligning equations with \& to ensure the equal signs are aligned vertically.
\begin{align}
a &= b + c \\
d &= e - f \\
\end{align}