Reciprocator

Part of speech: noun

Definitions

1. An individual or device that responds to an action, gesture, or feeling by giving back a similar reaction or motion; a mechanism that converts rotational movement into linear motion or vice versa; a person who returns a favor or responds in kind to another's behavior
2. Someone or something that mirrors or returns an action, sentiment, or motion, often involving mutual exchange; a machine component facilitating back-and-forth movement; an entity engaged in mutual response or exchange of actions or feelings
3. A person or apparatus characterized by mutual response or exchange, acting in return for an initial action or emotion; a mechanical element producing reciprocal movement; an agent who answers or reacts with corresponding behavior to another's initiative

Etymology: "Reciprocator" is simply "reciprocate" with the agent suffix "-or" added, meaning one who or that which reciprocates. The verb "reciprocate" comes from Latin "reciprocare," meaning to move back and forth, a sense that survives in the word's engineering use, where a reciprocating piston slides back and forth in a cylinder. The suffix has a long path into English. It descends from a Proto-Italic form and reached Latin as "-tor" and "-ator," then passed through Old French "-eor" before arriving in Middle English as "-our," which later became the "-or" spelling used in modern English. Because the suffix attaches to a verb stem, it is a productive way to name a doer, as in "actor" or "editor."

Synonyms: exchange partner, mutual giver

Antonyms: nonreciprocator