ANSI Common Lisp 15 Arrays 15.1 Array Concepts 15.1.1 Array Elements
188.8.131.52 Array Dimensions
An axis of an array is called a dimension.
Each dimension is a non-negative
if any dimension of an array is zero, the array has no elements.
It is permissible for a dimension to be zero,
in which case the array has no elements,
and any attempt to access an element
is an error. However, other properties of the array,
such as the dimensions themselves, may be used.
184.108.40.206.1 Implementation Limits on Individual Array Dimensions