A property associated with a square matrix \(\mathbf{M}\), written as \(|\mathbf{M}|\). For a two dimensional matrix it is equal to
\[ \begin{vmatrix} a & b\\ c & d \end{vmatrix} = ad - bc \]
The absolute value of the determinant of a \(n\) by \(n\) matrix is equal to the \(n\)-volume of the result of using it to transform the \(n\) dimensional unit cube.