Nitrite (noun)

1. A salt or ester of nitrous acid, typically having the formula NO2-.
2. A chemical compound used as a food preservative and color fixative.
3. A compound used to cure meats and fish.

Origin:

From nitr- + -ite, from the latin nitrum "saltpeter", from greek nitron.

Examples:

1. Nitrite is used to preserve hot dogs and bacon.
2. Nitrite is toxic if ingested in large amounts.
3. The nitrite in the meat caused a reaction with the stomach acid.
4. Nitrite is used to cure meats and fish.
5. The nitrite levels in the water were found to be too high.