Reagent

Part of speech: noun

Pronunciation: /ɹiˈeɪ.d͡ʒənt/

Definitions

1. A material utilized in chemical processes to induce reactions, analyze compounds, or facilitate transformations
2. A substance applied in laboratory settings to interact with other materials for the purpose of identification or quantification
3. A compound used in various scientific experiments to initiate chemical reactions, analyze substances, or assist in the detection of other chemicals

Etymology: Reagent is a word that sits in a neat family of parallels. English has act, action, and agent, and reaction has its counterpart in react. The source notes that reagent follows the same pattern, with react giving reaction and reagent giving reagency, so the word is tied to the verb "react" by formation as well as meaning. Its likely Latin ancestor is "reagō", a verb meaning to drive back or to act in response, which fits the idea of a substance that acts when something is brought against it. The Norwegian Bokmål "reagens" shows the same form, which suggests the term was shaped in parallel across European scientific languages rather than passed along from one to another. The exact route into English is uncertain, so it is best to think of reagent as a chemist's coinage built from familiar parts: the root of "react" plus the agent ending seen in words like "agent" itself.

Synonyms: chemical, substance, agent