- A matrix is a rectangular array of numbers, arranged in rows and columns.
- Order of a matrix = Number of rows in it x Number of columns in it
- Row matrix is a matrix with only one row.
- Column matrix is a matrix with only one column.
- Zero or Null matrix is a matrix in which every element is zero.
- Unit or Identity matrix is a square matrix in which the diagonal elements (top left to bottom right) are each equal to 1 and all the other non diagonal elements are zero (0). It is denoted by I.
- Two matrices are said to be compatible for multiplication, if the number of columns in the first matrix is the same as the number of rows in the second matrix.
