An array is typically a data structure meant to store a collection of elements to which is associated a given index. These elements are often in contiguous memory locations although this is not a requirement.
Multidimensional-arrays can be described as multi-dimensional tables. Each index used in order to find a given element is called a dimension.
Depending on the programming language, such a data structure can be achieved through a specific multi-dimension array data structure or in the shape of an "array of arrays" (also known as jagged arrays or Iliffe vector).
Multidimensional-arrays are often used to put values in a table format (e.g. rows and columns).
- C++ multidimensional arrays
- php multidimensional arrays
This StackOverflow thread provides some insight on the difference between multi-dimensional arrays and jagged arrays in C#.