The 1D-array is a special type of that represents a one-dimensional ordered sequence of scalar (i.e. non-array) data.
See also the for an example of a 1D-array of integers.
In Excel, it is represented by contiguous cells that may extend in either the horizontal or vertical direction.
The orientation of the cells is irrelevant.
For example, if a function expects as input a 1D-array, it makes no difference if that input is supplied as a single row or as a single column.
A cell containing the text [end] is itself not part of the array and indicates that the last array element is the preceding cell.
An empty array is an array with a zero number of elements and can be specified by a single cell containing the text [end]