nox

/ɛn əʊ ˈɛks/

nox means the Roman goddess of night.

nox is pronounced /ɛn əʊ ˈɛks/.

Why “nox” is a great word

The personification of night as a Roman goddess or, in photometry, a unit of illuminance equal to one millilux. Borrowed from Latin Nox ("night; the goddess Night"). Unlike "night" (the common term for the period of darkness) or "Nyx" (the Greek primordial deity), nox is a word reserved for classical myth or precise technical measurement—a term for darkness when it becomes an absolute or a quantity. It is the ink-black space between the stars in a Lucretian cosmos, the precise, feeble glow of a single distant candle measured by a cold instrument, and the heavy, sacred silence that falls after the final temple offering: a single syllable that carries both the weight of ancient prayer and the cool exactitude of scientific measure.

Etymology

Borrowed from Latin Nox.

name

The Roman goddess of night.

noun

The period of darkness in each twenty-four hours; a night.
Any of the various nitrogen oxides produced during combustion.e.g.“"The NOx and particulate reductions provide clean air in the cities and communities we serve. [...]"” — 2020 December 16, Daniel Puddicombe, “Treated DMUs become greener and cleaner”, in Rail, page 46:
millilux (unit of illuminance)

Definitions & examples from Wiktionary (CC BY-SA 3.0).

Words closest in meaning

By meaning, not spelling — each word's AI semantic fingerprint, nearest first.

nightertale 58% match — The period of night; nighttime. vs nox →
noctilucoid 58% match — Synonym of noctilucous. vs nox →
nightlike 57% match — Resembling night or some aspect of it; dark, tenebrous. vs nox →
nightgloom 57% match — Darkness of the night; night gloom. vs nox →
nightlessness 57% match — Absence of night. vs nox →
nocturn 56% match — The night office of the Christian liturgy of the Hours, such as is performed in monasteries. vs nox →
nighten 56% match — To become night or grow dark, as night. vs nox →
nighttime 55% match — The hours of darkness between sunset and sunrise; the night. vs nox →