Let $A$ be an $n\times n$ matrix. Recall that $C_{ij}$ is the $(i,j)$ cofactor of $A$. The matrix of cofactors of $A$ is the $n\times n$ matrix $C$ whose $(i,j)$ entry is $C_{ij}$.

The adjoint of $A$ is the $n\times n$ matrix $J=C^T$, the transpose of the matrix of cofactors.