ἔκκεντρος

Forms

ἔκκεντρος (ékkentros) m or f (neuter ἔκκεντρον); second declension^[1]

Etymology

It is formed from Ancient Greek ἐκ- (ek-, “out of”) + κέντρον (kéntron, “centre”), “out of the centre”.^[1][2][3]

Earliest recorded meaning

It is a term of Hellenistic astronomy, first found in Posidonius and Geminus, who use it of circles whose centre is not that of the earth or of the heavens, and Geminus applies it to the sun's orbit.^[4][5][6]

Semantic evolution

Under the Roman Empire the word stayed technical: Cleomedes, Theon of Smyrna and Ptolemy's Almagest speak of eccentric circles, and Proclus and Simplicius of eccentric spheres.^[4][5] In astrology Vettius Valens used it of stars that do not stand on a cardinal point of the zodiac, the opposite of ἔγκεντρος (énkentros).^[5][4] Derivatives include ἐκκεντρότης (ekkentrótēs) and the planetary term ἐκκεντρεπίκυκλος (ekkentrepíkuklos).^[1]

It passed into Latin as eccentros, and Medieval Latin eccentricus gave English eccentric in the early 15th century, first as a term of Ptolemaic astronomy; the sense of an odd person is from about 1817.^[1][3] Modern Greek έκκεντρος (ékkentros) continues the geometric sense, and as a noun names the eccentric of a machine, a sense taken from French excentrique.^[7]

Timeline

• 2nd–1st century BC – Posidonius uses it of the eccentric circles of the planets.^[4]
• 1st century BC – Geminus uses it of the sun's orbit.^[4][5][6]
• 2nd century AD – Cleomedes, Theon of Smyrna and Ptolemy use it in astronomy, and Vettius Valens in astrology.^[4][5]
• 5th–6th century AD – Proclus and Simplicius write of eccentric spheres.^[4]
• Early 15th century – English borrows eccentric through Medieval Latin and French.^[3]
• Modern Greek – The learned έκκεντρος (ékkentros) means eccentric in geometry and names a machine part.^[7]

Meanings

Adjective

1. (astronomy) Eccentric, having a centre other than the earth or the centre of the heavens, said of a circle or sphere.^[5][4]
2. (astrology) Not standing on a cardinal point of the zodiac.^[5][4]

Word family

• ἐκκεντρεπίκυκλος (ekkentrepíkuklos)
• ἐκκεντρίζω (ekkentrízō)
• ἐκκεντρότης (ekkentrótēs)

Related words

• κέντρον (kéntron)
• ἔγκεντρος (énkentros)
• Latin eccentros
• English eccentric

References

1. ^ a b c d e f g Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ Bailly, Anatole (2020), Dictionnaire grec-français, Bailly 2020 Hugo Chávez ed., ed. Gérard Gréco et al.
3. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e f g h i Rodríguez Adrados, Francisco, et al., eds. (1980–), Diccionario Griego-Español, Madrid: CSIC, http://dge.cchs.csic.es/xdge
5. ^ a b c d e f g Liddell, Henry George; Scott, Robert; Jones, Henry Stuart (1940), A Greek-English Lexicon, 9th ed., Oxford: Clarendon Press
6. ^ a b Keersmaekers, Alek (2021–2025), GLAUx: The Greek Language Automated corpus, https://github.com/alekkeersmaekers/glaux
7. ^ a b Ινστιτούτο Νεοελληνικών Σπουδών (Ίδρυμα Μανόλη Τριανταφυλλίδη) (1998), Λεξικό της κοινής νεοελληνικής, Thessaloniki: Aristotle University of Thessaloniki