# null

/ˈnəɫ/ (US) · /nˈʌl/ (UK)

Source: https://englishreference.com/word/null
Updated: 2026-06-20

## Senses

### 1. invalid or empty

adjective · CEFR B2 · Formal

having no legal power or being equal to nothing.

For teachers: having no legal force or validity; alternatively, representing a value of zero or an empty set.

- The judge declared that the old contract was null and void.
- The agreement was rendered null and void after it was discovered that one of the signatories had acted without proper legal authority.

Usage: Commonly used in the fixed phrase 'null and void'.

### 2. an empty value

noun · CEFR C1 · Technical

a value that means 'no data' or 'nothing' in a computer program.

For teachers: a special marker used in programming to indicate that a data element does not have a value.

- The program crashed because the database returned a null instead of a name.
- The developer implemented a check to ensure the function would not execute if the input variable was null.

Usage: Often functions as an uncountable noun in technical contexts.

### 3. null hypothesis

noun · CEFR C1 · Academic · Technical

the starting idea in a science test that says there is no change or no effect.

For teachers: the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

- The scientists failed to reject the null during their first experiment.
- Statistical significance was not reached, meaning the researchers could not disprove the null hypothesis regarding the drug's efficacy.

### 4. to remove software limits

verb · CEFR C2 · Slang · Technical

to break the security on a piece of software so it can be used for free.

For teachers: to remove digital rights management or licensing restrictions from software.

- He found a nulled version of the expensive photo editor online.
- Using nulled software is a significant security risk as the modified code often contains hidden malware or backdoors.

## Examples

- The database returned a null value for the missing phone number.
- If the user leaves the middle name field empty, the system records it as null in the profile.
- The experiment was deemed a failure when the results showed a null effect, suggesting that the new drug was no more effective than the existing placebo.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.