WordReference Random House Unabridged Dictionary of American English © 2026
ni′trogen tetrox′ide, [Chem.]
- Chemistrya poisonous compound, N2O4, occurring as a colorless, water-soluble solid or liquid, dissociating into NO2: used chiefly as an oxidizer, esp. in rocket fuels, as a nitrating agent, and as an intermediate in the manufacture of nitric acid.