Original: An m × 1 matrix (one column and m rows) is called a column vector and a 1 × n matrix (one row and n columns) is called a row vector.
Simplified: A matrix with m rows and n columns is called an m-by-n matrix (or m&times;n matrix) and m and n are called its dimensions. One column matrix A matrix, that has many rows, but only one column, is called a column vector.