<p><strong>Noun:</strong></p><ul><li>A blackish, resinlike substance derived from tropical plants of the genus <em>Strychnos</em>, especially <em>S. toxifera</em>, and from the root of pareira, used by certain South American Indians for poisoning arrows and employed in physiological experiments, medicine, etc., for arresting the action of motor nerves.</li><li>A plant yielding this substance.</li></ul>