Standard Lemma guide

zero-day

adj · noun · 6 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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1

adj

Meaning 1

Of warez, released less than a day after the official product release.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: computing, engineering, mathematics, natural-sciences, physical-sciences, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

adj

Meaning 2

Of a vulnerability, newly discovered, and therefore still not fixed and possibly exploited by hackers or other criminals.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Qualifier: computer security

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

3

adj

Meaning 3

Of an exploit or its threat or an attack, benefiting from a newly found and yet unpatched or unmitigated flaw in software or hardware; using a zero-day vulnerability.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Qualifier: computer security

Examples

  • 2005, Valdes et al, Recent Advances in Intrusion Detection Automatically creating reliable signatures of zero-day exploits is the focus of intense research efforts.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

4

adj

Meaning 4

Used other than figuratively or idiomatically: see zero, day.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Examples

  • Average residues of 1.44 and 2.18 mg/kg chlortetracycline were seen in liver and kidney, respectively, at zero-day withdrawal.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

5

noun

Meaning 5

A vulnerability that has been discovered recently, and is yet unpatched or unmitigated; a zero-day vulnerability.

Definition source: English Wiktionary via Wiktextract

Qualifier: computer security

Examples

  • New Internet Explorer zero-day exploited in Hong Kong attacks

Meaning relationships

Synonyms: none provided

Antonyms: none provided

6

noun

Meaning 6

A day without obligations, where one does not worry about being productive.

Definition source: English Wiktionary via Wiktextract

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

No etymology was provided for this word.