JavaScript is unique to have two nullish values: null and undefined. Semantically, their difference is very minor: undefined represents the absence of a value, while null represents the absence of an object.

Null often pops up in legal and scientific contexts; it was originally used in Scottish law and still carries the meaning "having no legal or binding force," especially in the phrase "null and void."

Tip This article is part of the Fundamentals section for developers who know at least one programming language and are learning C#. If you're new to programming, start with the Get started tutorials first. For the complete operator reference, see Member access operators and null-coalescing operators in the language reference.

Null character, the zero-valued ASCII character, also designated by NUL, often used as a terminator, separator or filler. This symbol has no visual representation.

It can be used on a type to control Nullability, it is then called the "Null Forgiving Operator". Basically, null! applies the ! operator to the value null. This overrides the nullability of the value null to non-nullable, telling the compiler that null is a "non-null" type.

The basic rule is simple: null should only be allowed when it makes sense for an object reference to have 'no value associated with it'. (Note: an object reference can be a variable, constant, property (class field), input/output argument, and so on.)

In computer science, a null value represents a reference that points, generally intentionally, to a nonexistent or invalid object or address. The meaning of a null reference varies among language implementations.

NULL definition: 1. having no legal force: 2. with no value or effect: 3. (of a set or matrix) containing nothing…. Learn more.

A NULL value represents an unknown, missing, or inapplicable data in a database field. It is not a value itself, but a placeholder to indicate the absence of data.

If a reference points to null then it always means that there is no value associated with it. In most cases, null has a more specific meaning that depends on the context.