A vector can be written as a matrix.
If vector v=v1i+v2j+v3k, where i, j, k are orthogonal unit vectors in 3-space, then the vector can be written as a 1 by 3 matrix: v=( v1 v2 v3 ). This vector has only one row, but 3 columns corresponding to the dimensions in 3-space. A 1 by n matrix could represent a vector in hypothetical n-space.