Null

The value null is a reference that does not refer to anything.

Related concepts:  ValueReference

Closest Wikipedia entry:  Null pointer — In computing, a null pointer or null reference is a value saved for indicating that the pointer or reference does not refer to a valid object. Programs routinely use null pointers to represent conditions such as the end of a list of unknown length or the failure to perform some action; this use of null pointers can be compared to nullable types and to the Nothing value in an option type. A null pointer should not be confused with an uninitialized pointer: a null pointer is guaranteed to compare unequal to any pointer that points to a valid object.

Misconceptions about Null

7 documented Misconceptions

BoxedNull — Java

Passing null to a wrapper class constructor creates an object representing the absence of a value

NullAndUndefinedAreTheSame — JavaScript

The values null and undefined are the same

NullIsObject — Java

null is an object

NullIsObject — JavaScript

null is an object

OutOfBoundsElementsAreNull — Java

Out-of-bounds array elements are null

ThisCanBeNull — Java

this can be null

ThisInConstructorIsNull — Java

In a constructor, this is null