* The standard definition for an array is a linear collection of elements, where the elements
can be accessed via indices, which are usually integers used to compute offsets.

A JavaScript array is actually a specialized type of JavaScript object, with the indices
being property names that can be integers used to represent offsets. However, when
integers are used for indices, they are converted to strings internally in order to conform
to the requirements for JavaScript objects.
 

Accessor functions  
functions that retrieve the indices of wanted values, for example in javascript, the function Array.prototype.indexOf() is an Accessor function.
To retrieve the value of an element in an array you use an expression, denoted using the bracket syntax: array[10].
this expression does a resolution to a variable adress in memory that holds an array object, than accesses the memory adress designated for the item at index of 10 in the space designated for the array.
In javascript arrays are objects, so this bracket expression will retrieve the value of the "10" property under the array object, stored in the adress reached by resolution of the array variable.

Mutator Functions
Mutator functions change the structure of an array variable, for example add items to the array, remove items, or retrieve parts of the array.
For example in javascript: pop(), push(), shift(), unshift(), splice(), concat()

Iterator Function
Iterator functions apply a selected function to each array item, either returning a value, a set of values, or a new array after all array item have been iterated over with the selected function.
In javascript examples for these kind of functions are: forEach(), map(), reduce(), filter(),findIndex() (not an accessor function since it applies a function to each item)
 

Multi-Dimensional Arrays (arrays of arrays or matrix) 
To represent complex data structures mutidimesional arrays are often used, for example for image processing, where an image is a matrix of pixels represented by a two dimensional array, representing the X & Y axis to access the different pixels in the grid.
To create multidimensional arrays its better to use the grid approach of columns and rows, defining a function that takes a number of row a colums.

Multi-Dimensional Jagged Arrays
Are multidimensional array that contain diferent sizes of arrays for each column or row.

Sparse Arrays: 
Sparse arrays are arrays that have undassigned (undefined) elements in it, making the real size of the array different than the arrays size.