Zilde

Zilde is the empty numeric vector. It is the shape of any scalar, although its own shape is  (Zilde's shape cannot be Zilde, as that would mean it were a scalar). Zilde is equivalent to  or.

Zilde is notable for being the only APL glyph which represents an array rather than a primitive function or primitive operator. In most APLs it is the only array literal which is produced using its own token rather than being part of a family of array literals like numeric literals, strings, or system constants.