An array is a systematic arrangement of similar objects, usually in rows and columns.
The little push-buttons on the upper part of the right electronic device are arranged in an array with 3 columns and 4 rows. The two devices themselves form a very simple array of 2 columns and 1 row.
Things called an array include:
Music
In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the sums of their horizontal segments form a succession of twelve-tone aggregates