1. An idea, language, term, or other thing that has developed from something else that is similar to it.
2. A word that is formed from another word; for example, "quickly" from "quick" or "electricity" from "electric".
3. A chemical substance that is formed from a related substance; such as, an opium derivative.
4. A financial product that can be traded and whose value depends on the value of some other asset or combination of assets.

A contract, or security, that derives its value from that of another form ov security or from the value of a rate; such as, interest or a currency exchange, or the index of a stock index.

Derivatives often take the form of customized contracts transacted outside of security exchanges, while other contracts; such as, standard index options and futures, are openly traded on such exchanges.

A derivative is also defined as a contract to buy or to sell an asset or to exchange cash, based on a specified condition, event, occurrence, or another contract.

5. Etymology: from French derivatif (15th century), from Latin derivativus, from the past participle stem of derivare, "to lead or to draw off (a stream of water) from its source"; from de, "from" + rivus. "stream".