A subarray is commonly defined as a part or section of an array. An array is a set of variables that a programmer defines collectively. Instead of creating separate variables, the programmer can declare a single array with multiple values labeled.
Programmers can perform many of the same options on a subarray that they can perform on the entire array. Allowing operations on a subarray helps make these tools more versatile for storing multiple variables in a single designated set.
Techopedia explains Subarray
In various programming languages, uses of a subarray, such as sending the data set to or from a method or function, will generally include much of the same syntax used with the entire array, with some subtle differences. Typically, the name of the array will be reference first, and the exact subarray or portion of the array will be written in parentheses or brackets.
In using a subarray, programmers have to pay the same kind of attention to consistency that they would when using an entire array or a single variable. This includes making sure that the values passed from one method or function to another don’t get changed through a bug or glitch in the code, and that all parts of the code that need these values can access them. It can be useful to go through a written program in debug mode to look at how values are assessed line by line if there is any problem with the use of a subarray.