You searched for: “column order
column order (s) (noun), column orders (pl)
In computer programming, a method of defining a matrix by naming the elements one column at a time, as opposed to row order: The computer technician installed a new column order to facilitate the creation of textual content.

A "matrix" in this context is an array of symbols arranged in rows and columns.

This entry is located in the following unit: English Words in Action, Group C (page 5)