Nox

//ɛn əʊ ˈɛks// name, noun

name, noun ·Uncommon ·Advanced level

Definitions

Noun
  1. 1
    The period of darkness in each twenty-four hours; a night.
  2. 2
    millilux (unit of illuminance) rare
  3. 3
    Alternative form of NOx (nitrogen oxides) alt-of, alternative, uncountable
  4. 4
    Any of the various nitrogen oxides produced during combustion.

    ""The NOx and particulate reductions provide clean air in the cities and communities we serve. [...]""

  5. 5
    Alternative form of nox (“nitrous oxide”). alt-of, alternative, uncountable
Show 1 more definition
  1. 6
    Abbreviation of nitrous oxide (“N₂O”). abbreviation, alt-of, uncountable

    "Near-synonym: nos"

Proper Noun
  1. 1
    The Roman goddess of night. Roman

Example

More examples

""The NOx and particulate reductions provide clean air in the cities and communities we serve. [...]""

Etymology

Etymology 1

Etymology tree Proto-Indo-European *nókʷts Proto-Italic *nokts Latin noxlbor. English nox Learned borrowing from Latin nox, from Proto-Italic *nokts, from Proto-Indo-European *nókʷts.

Etymology 2

From Latin nox (“night; darkness”), by analogy with lux from Latin lūx (“light; daylight, day”). Doublet of night.

Etymology 3

From N (“nitrogen”) + ox (“oxide”).

Etymology 4

From Latin Nox.

Etymology 5

From N (“nitrogen”) + O (“oxygen”) + x (“x substitution value”).

Etymology 6

From N (“nitrous”) + Ox (“oxygen”).

Related phrases

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.