(n.) 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.
(n.) 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.
(n.) Something demanded or asserted; especially, a position or supposition assumed without proof, or one which is considered as self-evident; a truth to which assent may be demanded or challenged, without argument or evidence.
(n.) The enunciation of a self-evident problem, in distinction from an axiom, which is the enunciation of a self-evident theorem.
(v. t.) To beg, or assume without proof; as, to postulate conclusions.
(v. t.) To take without express consent; to assume.