Any element $A^{i}_{j}$ of $A$ is a $1\times1$ minor of $A$

Question

In a textbook is said

"Any element $A^{i}_{j}$ of $A$ is a $1\times1$ minor of $A$"

How is this should be understood? As I know minor of $A^{i}_{j}$ element is the determinant of the matrix left after removing $i^{th}$ row and $j^{th}$ column.

Answer 1

The determinant of a matrix formed by removing one row and one column is just one case of a minor: a $(n-1) \times (n-1)$ minor if the original matrix is $n \times n$. In general, a $k \times k$ minor is the determinant of any square submatrix, formed by deleting $n-k$ rows and $n-k$ columns. If $k=1$, it's just a single element of the matrix.