radius

See also: Radius, RADIUS, and radíus

English

The radius of a circle, shown in red

Etymology

Borrowed from Latin radius (“ray”). Doublet of ray.

Pronunciation

• enPR: rā'-dē-əs, IPA^(key): /ˈɹeɪ.di.əs/

• Audio (US):

  (file)

• Rhymes: -eɪdiəs
• Hyphenation: ra‧di‧us

Noun

radius (plural radii or radiuses)

1. (anatomy) The long bone in the forearm, on the side of the thumb.
   • 1808, John Barclay, The Muscular Motions of the Human Body‎, →OCLC, page 396:

     It is also obvious, and proved by experiment, that the rotatory motions observed in the hand proceed from the rotatory motions of the radius.

2. (zoology) The lighter bone (or fused portion of bone) in the forelimb of an animal.
3. (entomology) One of the major veins of the insect wing, between the subcosta and the media; the vein running along the costal edge of the discal cell.
4. (geometry) A line segment between any point of a circle or sphere and its center.

   Fatima claims to have visited all the bars within a five-mile radius of her Manhattan apartment.

5. (geometry) The length of this line segment.
6. Anything resembling a radius, such as the spoke of a wheel, the movable arm of a sextant, or one of the radiating lines of a spider's web.
   • 1674, Robert Hooke, Animadversions on the Firſt Part of the Machina Coelestis of the […] Aſtronomer Johannes Hevelius […] ‎, page 43:

     […] I can do more with a Quadrant, Sextant or Octant, of 1 foot Radius, furniſhed with Teleſcopical Sights and Screws, then ^[sic] can poſſibly be done with any other Inſtrument, furniſhed only with Common Sights, though 10, 20, 30, nay threeſcore foot Radius; […]

Synonyms

• (vein of insect wing): R

Derived terms

• Bohr radius
• Debye radius
• hydraulic radius
• potato radius
• radius arm
• radius bar
• radius of action
• radius of convergence
• radius of curvature
• radius of gyration
• radius rod
• radius vector
• Schwarzschild radius
• sight radius
• van der Waals radius

 

Related terms

• radial
• radiad
• radiate, radiation

Translations

bone (human)

Arabic: كُعْبُرَة f (kuʕbura) Egyptian Arabic: كعبرة f (kuʕbura) Armenian: ճաճանչոսկր (hy) (čačančʻoskr) Bulgarian: лъчева кост f (lǎčeva kost) Catalan: radi (ca) m Chinese: Mandarin: 橈骨／桡骨 (zh) (ráogǔ) Czech: vřetenní kost f Dutch: spaakbeen (nl) n, radius (nl) m Esperanto: radiuso Finnish: värttinäluu (fi) French: radius (fr) m German: Speiche (de) f, Radius (de) m Greek: κερκίδα (el) f (kerkída) Hungarian: orsócsont (hu) Ido: radiuso (io) Irish: gaghéag f Italian: radio (it) m Japanese: 橈骨 (ja) (とうこつ, tōkotsu) Kalmyk: шу (şu) Kannada: ಮುಂಗೈ ಮೂಳೆ (kn) (muṅgai mūḷe) Kazakh: кәрі жілік (kärı jılık) Korean: 노뼈 (ko) (noppyeo), 요골 (yogol) Kurdish: Northern Kurdish: kewere Malay: radius (ms) Maori: āpiti Mongolian: Cyrillic: шуу (mn) (šuu), шуу яс (šuu jas) (China) Old English: hresel Polish: kość promieniowa f pl Portuguese: rádio (pt) m Romanian: radius (ro) n Russian: лучева́я кость f (lučevája kostʹ) Serbo-Croatian: žbica (sh) f, palčana kost f Spanish: radio (es) m Telugu: రత్ని (te) (ratni) Ukrainian: променева кістка f (promeneva kistka) Vietnamese: xương quay Volapük: radiut Welsh: gwäell y fraich f

line segment

Afrikaans: radius Arabic: نُصْف قُطْر m (nuṣf quṭr), شُعَاع m (šuʕāʕ) Armenian: շառավիղ (hy) (šaṙaviġ) Basque: erradio Belarusian: ра́дыус m (rádyus) Breton: skin (br) m Bulgarian: ра́диус m (rádius) Burmese: အချင်းဝက် (my) (a.hkyang:wak) Catalan: radi (ca) m Cebuano: tungatid Chinese: Mandarin: 半徑／半径 (zh) (bànjìng) Czech: poloměr (cs) m Danish: radius (da) Dutch: straal (nl) f Esperanto: radiuso Estonian: raadius (et) Faroese: radius m Finnish: säde (fi) French: rayon (fr) m Friulian: rai m Galician: raio (gl) m Georgian: რადიუსი (radiusi) German: Radius (de) m, Halbmesser (de) m (rare) Greek: ακτίνα (el) f (aktína) Gujarati: ત્રિજ્યા (gu) f (trijyā) Hebrew: רַדְיוּס (he) m (rádyus) Hindi: त्रिज्या (hi) f (trijyā) Hungarian: sugár (hu) Icelandic: radíus (is) m, geisli (is) m Ido: radiuso (io) Indonesian: radius (id) Irish: ga m Italian: raggio (it) Japanese: 半径 (ja) (はんけい, hankei) Kannada: ತ್ರಿಜ್ಯ (kn) (trijya) Kazakh: радиус (radius) Korean: 반지름 (ko) (banjireum), 반경 (ko) (ban'gyeong) Kurdish: Northern Kurdish: nîvtîre Latvian: rādiuss (lv) m Lithuanian: spindulys m Macedonian: радиус m (radius), полупре́чник m (polupréčnik, literally “semidiameter”) Malay: jejari (ms) Maori: pūtoro Marathi: त्रिज्या f (trijyā) Mongolian: радиус (mn) (radius) Norwegian: Bokmål: radius (no) m Nynorsk: radius m Persian: شعاع (fa) (šo'â') Polish: promień (pl) m Portuguese: raio (pt) m Punjabi: ਰੇਡੀਅਸ (reḍīasa) Romanian: rază (ro) f Russian: ра́диус (ru) m (rádius) Scottish Gaelic: spòg f Serbo-Croatian: Cyrillic: полупречник m Roman: poluprečnik m Slovak: polomer m Slovene: polmer (sl) m Spanish: radio (es) m Swedish: radie (sv) Tagalog: lihit Telugu: వ్యాసార్థము (vyāsārthamu) Thai: รัศมี (th) (rát-sà-mǐi) Turkish: yarıçap (tr) Ukrainian: ра́діус (uk) m (rádius) Urdu: رداس m (radās) Vietnamese: bán kính (vi) Volapük: raid Welsh: radiws m Yiddish: ראַדיוס m (radyus)

length of this line segment

Armenian: շառավիղ (hy) (šaṙaviġ) Belarusian: ра́дыус m (rádyus) Bulgarian: ра́диус m (rádius) Catalan: radi (ca) m Chinese: Mandarin: 半徑／半径 (zh) (bànjìng) Czech: poloměr (cs) m Dutch: straal (nl) f Finnish: säde (fi) French: rayon (fr) m German: Radius (de) m, Halbmesser (de) m (rare) Hungarian: sugár (hu) Icelandic: radíus (is) m, geisli (is) m Irish: ga m Italian: raggio (it) m Japanese: 半径 (ja) (はんけい, hankei) Korean: 반지름 (ko) (banjireum) Macedonian: радиус m (radius), полупре́чник m (polupréčnik) Malay: jejari (ms) Marathi: त्रिज्या f (trijyā) Norwegian: Bokmål: radius (no) m Nynorsk: radius m Polish: promień (pl) m Portuguese: raio (pt) m Romanian: rază (ro) f Russian: ра́диус (ru) m (rádius) Serbo-Croatian: Cyrillic: полупречник m Roman: poluprečnik m, polumjer (sh) m (Croatia) Slovene: polmer (sl) m Spanish: radio (es) m Swedish: radie (sv) Ukrainian: ра́діус (uk) m (rádius) Volapük: raid Welsh: radiws m

Verb

radius (third-person singular simple present radiuses, present participle radiusing, simple past and past participle radiused)

1. (transitive) To give a rounded edge to.
   • 2014, Anil Mital, Anoop Desai, Anand Subramanian, Product Development, page 358:

     A comfortable grip is ensured by smoothing the surface of the handle and radiusing the edge.

See also

• ulna
• semidiameter
• Radius on Wikipedia.Wikipedia
• Radius (bone) on Wikipedia.Wikipedia

Anagrams

• Darius

Crimean Tatar

Other scripts
Cyrillic	радиус
Roman

Etymology

Borrowed from Russian радиус (radius), from Latin radius.

Noun

radius

1. radius (line segment or length of this line segment)

Declension

	singular	plural
nominative	radius	radiuslar
genitive	radiusnıñ	radiuslarnıñ
dative	radiusqa	radiuslarğa
accusative	radiusnı	radiuslarnı
locative	radiusta	radiuslarda
ablative	radiustan	radiuslardan

Declension of radius

References

• Mirjejev, V. A., Usejinov, S. M. (2002) Ukrajinsʹko-krymsʹkotatarsʹkyj slovnyk [Ukrainian – Crimean Tatar Dictionary]‎, Simferopol: Dolya, →ISBN
• “radius”, in Luğatçıq (in Russian)

Danish

Danish Wikipedia has an article on:

radius

Wikipedia ^da

Etymology

Borrowed from Latin radius.

Noun

radius c (singular definite radien or radiusen, plural indefinite radier or radiuser)

1. (geometry) radius

References

• “radius” in Den Danske Ordbog

Esperanto

Verb

radius

1. conditional of radii

Faroese

Noun

radius m (genitive singular radius, plural radiusar)

1. (geometry) radius

Declension

m52	Singular		Plural
	Indefinite	Definite	Indefinite	Definite
Nominative	radius	radiusin	radiusar	radiusarnir
Accusative	radius	radiusin	radiusar	radiusarnar
Dative	radiusi	radiusinum	radiusum	radiusunum
Genitive	radius	radiussins	radiusa	radiusanna

French

Etymology

Borrowed from Latin radius. Doublet of rai, which was inherited.

Pronunciation

• IPA^(key): /ʁa.djys/

• Audio:

  (file)

Noun

radius m (plural radius)

1. (anatomy) radius

Further reading

• “radius”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.

Anagrams

• durais

Ido

Verb

radius

1. conditional of radiar

Indonesian

Indonesian Wikipedia has an article on:

radius

Wikipedia ^id

Etymology

Learned borrowing from Latin radius.

Pronunciation

• IPA^(key): /raˈdiʊs/
• Hyphenation: ra‧di‧us

Noun

radius (first-person possessive radiusku, second-person possessive radiusmu, third-person possessive radiusnya)

1. radius:
   1. (mathematics) a line segment between any point of a circle or sphere and its center; the length of this line segment.

      Synonym: jari-jari

   2. (anatomy) the long bone in the forearm, on the side of the thumb.

      Synonym: pengumpil

2. area of a circle, commonly with epicenter as center.

Derived terms

• radius pelayaran

 

Further reading

• “radius” in Kamus Besar Bahasa Indonesia, Jakarta: Agency for Language Development and Cultivation – Ministry of Education, Culture, Research, and Technology of the Republic of Indonesia, 2016.

Latin

Etymology

Of uncertain origin.^[1] Some connect it with rādīx and rāmus. Tucker suggests Proto-Indo-European *neredʰ- (“extend forth, rise, outward”) akin to Sanskrit वर्धते (vardhate, “rise, grow”), or from Ancient Greek ἄρδις (árdis, “sharp point”).^[2] May ultimately be from Proto-Indo-European *reh₁t- (“bar, beam, stem”).

Pronunciation

• (Classical Latin) IPA^(key): /ˈra.di.us/, [ˈräd̪iʊs̠]
• (modern Italianate Ecclesiastical) IPA^(key): /ˈra.di.us/, [ˈräːd̪ius]

Noun

radius m (genitive radiī or radī); second declension

1. a staff, rod
   1. a spoke of a wheel
   2. a rod for measurement
   3. the radius of a circle; a rotating radial arm
   4. (weaving) a shuttle
   5. (poetic) a bolt or shaft
   6. the spur of a bird's leg
   7. the tail-spine of a stingray
   8. (anatomy) the radius (the outer bone of a forearm)
2. a ray of light (also reflected)
   • 29 BCE – 19 BCE, Virgil, Aeneid 4.118-119:

     “[...] ubi prīmōs crāstinus ortus
     extulerit Tītān, radiīsque retēxerit orbem.”

     “[...] when at tomorrow’s early dawn the Titan [Sun] will have risen, and with [his] rays revealed the world.”

   • 8 CE, Ovid, Fasti 6.717:

     At pater Hēliadum radiōs ubi tīnxerit undīs

     But when the father of the Heliades shall have dipped his rays in the waves [...].
     (The father is the sun god; see: Heliades.)

   1. (according to an ancient theory of vision) a ray extending from the eye to the object seen
3. the name of an elongated variety of olive
4. the name of a rod with which geometers make figures in dust, also known as a virga

Declension

Second-declension noun.

Case	Singular	Plural
Nominative	radius	radiī
Genitive	radiī radī1	radiōrum
Dative	radiō	radiīs
Accusative	radium	radiōs
Ablative	radiō	radiīs
Vocative	radie	radiī

¹Found in older Latin (until the Augustan Age).

Derived terms

• radiō
• radiolus

Descendants

• → Albanian: rreze
• Aromanian: aradzã, radzã
• Catalan: raig
  • →? Sardinian: raxu
• Dalmatian: rus, ruaz
• Old French: rai
  • French: rai
  • → English: ray
• Friulian: rai
• Galician: raia, raio, raxo
• Italian: raggio
  • Sicilian: raggiu (italianized, palatalized variant)
• Mirandese: raio
• Mozarabic: ראיה (rʔyh)
• Occitan: rai
• Portuguese: raia, raio
• Romanian: rază
• Sardinian: (ar)raju, (ar)rag(g)iu, arràciu, ràdiu
• Sicilian: raja
• Spanish: raya, rayo, raza
  • → Sardinian: razu m, raza f, rasu
• Venetian: rajo
• → Welsh: rhaidd

Learned borrowings

• → Catalan: radi
• → Italian: radio
• → English: radius, radio-, radio
• → French: radius
• → Galician: radio
• → German: Radius
• → Portuguese: rádio
• → Romanian: radius
• → Russian: ра́диус (rádius)
• → Sicilian: ràdiu
• → Spanish: radio

References

1. De Vaan, Michiel (2008) “radius”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, page 512
2. Tucker, T.G., Etymological Dictionary of Latin, Ares Publishers, 1976 (reprint of 1931 edition).

Further reading

• “radius” on page 1731 of the Oxford Latin Dictionary (2nd ed., 2012)
• “radius”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “radius”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• radius in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• radius in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
• “radius”, in Harry Thurston Peck, editor (1898), Harper's Dictionary of Classical Antiquities, New York: Harper & Brothers
• “radius”, in William Smith et al., editor (1890), A Dictionary of Greek and Roman Antiquities, London: William Wayte. G. E. Marindin

Norwegian Bokmål

Norwegian Wikipedia has an article on:

radius

Wikipedia ^no

Etymology

Borrowed from Latin radius.

Noun

radius m (definite singular radien or radiusen, indefinite plural radier, definite plural radiene)

1. (geometry) radius

References

• “radius” in The Bokmål Dictionary.

Norwegian Nynorsk

Norwegian Nynorsk Wikipedia has an article on:

radius

Wikipedia ⁿⁿ

Etymology

Borrowed from Latin radius.

Noun

radius m (definite singular radiusen, indefinite plural radiusar, definite plural radiusane)

1. (geometry) radius

References

• “radius” in The Nynorsk Dictionary.

Romanian

Etymology

Borrowed from French radius, Latin radius. Compare the inherited doublet rază (“ray”).

Noun

radius n (plural radiusuri)

1. (anatomy) radius (bone)

Related terms

• radiu