Definition

1. Noun:
   • A poisonous red-brown gas (NO): A colorless to reddish-brown gas with the chemical formula NO, formed by the oxidation of nitrogen. It is a toxic air pollutant but also functions as an important signaling molecule in the human body.

Usage

• As a subject or object: "Nitric oxide" is used as a countable or uncountable noun to refer to the gaseous compound itself.
  • Nitric oxide is produced by the combustion of fossil fuels.
  • The enzyme synthesizes nitric oxide from arginine.

Examples

• Scientific/Medical Context:
  • Nitric oxide acts as a vasodilator, relaxing blood vessels.
  • Researchers are studying the role of nitric oxide in neural communication.
• Environmental Context:
  • Vehicle emissions are a major source of nitric oxide in urban air.

Advanced Usage

• "Nitric oxide synthase": The enzyme responsible for producing nitric oxide in the body.
  • Inhibition of nitric oxide synthase can affect blood pressure.
• "Nitric oxide donor": A compound that releases nitric oxide.
  • Some medications are nitric oxide donors used to treat heart conditions.

Variants and Related Words

• Nitrogen monoxide: A less common synonym for nitric oxide.
• NO: The standard chemical abbreviation.
• Nitrous oxide (N₂O): A different compound (laughing gas); note the distinction.

Synonyms

• Nitrogen monoxide (scientific synonym)

Related Phrases/Compounds

• Nitric oxide signaling: The biological process involving NO as a messenger.
  • Nitric oxide signaling is crucial for the immune response.

Noun

1. a poisonous red-brown gas (NO)