noun

• (rare) millilux (unit of illuminance)
• (Roman mythology) The Roman goddess of night.
• (chemistry) Any of the various nitrogen oxides produced during combustion.
• Alternative form of NOx (nitrogen oxides) [(chemistry) Any of the various nitrogen oxides produced during combustion.]
• Abbreviation of nitrous oxide. [(inorganic chemistry) A non-flammable gas (N₂O) commonly used in surgery and dentistry for its anaesthetic and analgesic effects and in motorsport for bursts of added power.]
• (automotive performance) Alternative form of nox [(rare) millilux (unit of illuminance)]