radius Latin · revision 3063

+ {{infobox|confidence=uncertain|attested=Plautus}}

+

+ ==Pronunciation==

+ * IPA (Classical): [ˈra.di.ʊs]^(Wiktionary)

+ * IPA (Ecclesiastical): [ˈraː.di.us]^(Wiktionary)

+

+ ==Forms==

+ '''radius''' ''m'' (genitive radiī or radī); second declension^(Wiktionary)

+

+ ==Etymology==

+ The origin is uncertain.^(de Vaan 2008)^(Wiktionary)^(OLD 2012) Walde–Hofmann and Pokorny connected it with [[radix|alt=rādīx]] “root”, but de Vaan finds this unlikely because the meanings are so different, and sees no clear root for it.^(de Vaan 2008)^(Wiktionary) The TLL derives it from a root *radh- “to shine”, comparing [[non|röðull|t=sun]].^(TLL)

+

+ ==Earliest recorded meaning==

+ It is found from Plautus onwards,^(de Vaan 2008)^(Köbler 2010) whose boastful soldier wants his shield to shine brighter “than the rays of the sun on a clear day”.^(OLD 2012)

+

+ ==Semantic evolution==

+ It meant a [[m|en|ray]] of light, as in Ennius, and the spoke of a wheel, as in Virgil.^(OLD 2012) It was a staff or stake, and especially the pointed rod with which geometers drew figures in the sand, so that Cicero calls Archimedes a man “of the dust and the rod”.^(OLD 2012)^(Gaffiot 2016)

+

+ It also meant the radius of a circle, a weaver's shuttle, the spur on a bird's leg, the radius bone of the forearm, and a long kind of olive, as in Virgil.^(Wiktionary)^(OLD 2012) Medieval writers used it in optics for a ray.^(DMLBS) It survives as Italian ''raggio'', French ''rai'', Spanish ''rayo'', Portuguese ''raio'' and Romanian ''rază''.^(Wiktionary) English ''ray'' came through Old French in the early 14th century, and ''radius'' was taken from Latin in the 1590s.^(Etymonline)

+

+ ==Timeline==

+ * c. 250–184 BC – Plautus uses it for the rays of the sun.^(OLD 2012)^(Köbler 2010)

+ * 204–169 BC – Ennius uses it for rays of light.^(OLD 2012)^(Köbler 2010)

+ * 81–43 BC – Cicero uses it for the geometer's rod.^(OLD 2012)^(Köbler 2010)

+ * 70–19 BC – Virgil uses it for spokes and for a kind of olive.^(OLD 2012)^(Köbler 2010)

+ * early 14th century – English ''ray'' is first recorded.^(Etymonline)

+ * 1590s – English ''radius'' is first recorded.^(Etymonline)

+

+ ==Meanings==

+ ===Noun===

+ # A [[m|en|ray]] (of light).^(OLD 2012)^(Lewis & Short 1879)

+ # A [[m|en|spoke]] (of a wheel).^(OLD 2012)^(Wiktionary)

+ # A staff, rod; a stake.^(Lewis & Short 1879)^(Gaffiot 2016)

+ # A geometer's rod (for drawing).^(OLD 2012)^(Gaffiot 2016)

+ # The radius (of a circle).^(Wiktionary)

+ # A weaver's [[m|en|shuttle]].^(Wiktionary)

+ # The radius bone (of the forearm).^(Wiktionary)

+ # A long variety of olive.^(OLD 2012)^(Wiktionary)

+

+ ==Word family==

+ * [[radiātus]]

+ * [[radiolus]]

+ * [[radiōsus]]

+ * [[radiō]]

+

+ ==Related words==

+ * [[en|ray]]

+ * [[en|radius]]

+ * [[en|radiant]]

+ * [[en|radio]]

+

+ ==References==

+ {{reflist}}