Reagent (noun)

A substance used in a chemical reaction to detect, measure, or produce another substance.

Origin:

Early 19th century: from french réactif, from réagir "react", from latin re- "again" + agere "to do".

Examples:

1. The reagent was added to the test tube to initiate the reaction.
2. The reagent was carefully selected to ensure accurate results.
3. The reagent was heated to a high temperature to increase its reactivity.
4. The reagent was carefully calibrated to provide precise measurements.
5. The reagent was stored in a cool, dry place to prevent contamination.