- [Zoöl] Any Old Word rodent of the genus Hystrix, having the back covered with long, sharp, erectile spines or quills, sometimes a foot long. The common species of Europe and Asia (Hystrix cristata) is the best known.
- [Zoöl] Any species of Erethizon and related genera, native of America. They are related to the true porcupines, but have shorter spines, and are arboreal in their habits. The Canada porcupine (Erethizon dorsatus) is a well known species.
Etymology: OE. porkepyn porpentine, OF. porc-espi, F. porc-épiccf. It. porco spino porco spinoso, Sp. puerco espino puerco espin, fr. L. porcus swine + spina thorn, spine). The last part of the French word is perhaps a corruption from the It. or Sp.; cf. F. épi ear, a spike of grain, L. spica. See Pork Spike a large nail, Spine