What does the word array mean in math?

Answer 1

An array is a set of numbers that form some sort of regular arrangement. A linear array is a 1-dimensional array consisting of a row or a column of a set of numbers. A 2-dimensional array is a rectangular arrangement of numbers. And there are arrays with higher dimensions.

The elements of an array need not be numbers: they could be variables, functions or expressions.

In other words, it's a picture to describe a multiplication problem.

Answer 2

A 2-dimensional array is a rectangular arrangement of numbers. There can be multi-dimensional arrays.