Null

Null may refer to:

Science, technology, and mathematics

Null (SQL) (or NULL), a special marker and keyword in SQL indicating that something has no value
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.
Null device, a special computer file that discards all data written to it
Null modem, a specially wired serial communications cable
Null object pattern, a software design pattern using an object with defined neutral behavior
Null pointer (sometimes written NULL, nil, or None), used in computer programming for an uninitialized, undefined, empty, or meaningless value
Null route, a network route that goes nowhere
Null string, the unique string of length zero (in computer science and formal language theory)
Null-terminated string, a character string of which the length is determined by the first null-character (in programming language C and related languages)
Nullable type, a feature of some statically-typed programming languages which allows a data type to be set to the special value NULL

Null (mathematics), a zero value in several branches of mathematics
Null set, a set that is negligible in some sense
- Also an older term for the empty set

Null (physics), a point in a field where the field quantity is zero
Null (radio), a concept in electromagnetism
Null vectors or curves in the causal structure of a Lorentzian manifold such as a Minkowski space-time

Null allele, in genetics
Null cipher, a ciphertext symbol
Null hypothesis, a concept in statistical hypothesis testing
Null morpheme, a concept in linguistics
Null result, the absence of a hypothesized effect in the outcome of a scientific experiment

Null, an identity of the character Gray Fox in the Metal Gear Solid: Portable Ops video game
Null, man-eating sentients in the Downs-Lord Triptich books by John Whitbourn
Null, the Living Darkness, a Marvel Comics character
Null, a villain from Teenage Mutant Ninja Turtles Adventures
Nulls, worm-like remains of defeated characters in the animated program ReBoot
Type: Null, a Gen VII Pokémon species introduced in Pokémon Sun and Moon

Null and void, having no legal validity
Null-A, a term used in science fiction, referring to Korzybski's notation ${\overline {A}}$ as an abbreviation for "non-Aristotelian" logic
Stunde Null, a term used in Germany to mark the end of the Second World War