In JavaScript, an array is a data structure used to store multiple values of any data type sequentially. Arrays allow you to group together related data items under a single variable name. Each value in an array is called an element, and each element is accessed by its index, starting from 0.

Example: Here, the variable numbers is assigned an array containing five numeric elements [1, 2, 3, 4, 5]. The elements are enclosed within square brackets ([]) and separated by commas. Each element has a numeric value, and they are stored sequentially in the array.

[ 1, 2, 3, 4, 5 ]