ἀκτίς

Ancient Greek

From an uncertain source apparently shared with Sanskrit अक्तु (aktú, “beam, ray”),^[1] perhaps:

Proto-Indo-European *h₂ekt- (“beam”), from an unidentified root;
Proto-Indo-European *h₂eḱ- (“sharp point”), which would exclude the Sanskrit;
Proto-Indo-European *n̥kʷt-ín-, *n̥kʷt-ú-, from *nokʷt- (“night”), with an obscure semantic development, perhaps “end of the night” which shifted to “dawn”, as paralleled by Gothic 𐌿𐌷𐍄𐍅𐍉 (uhtwō, “dawn”), and then “first light of dawn; ray of (dawn sun)light”. This is evidenced by the night-related meanings in the Sanskrit cognate.^[2] However, Beekes rejects this etymology due to the lack of evidence for a labiovelar.

The suffix is unexplained in any case.

ᾰ̓κτῑ́ς • (ăktī́s) f (genitive ᾰ̓κτῖνος); third declension

Third declension of ἡ ᾰ̓κτῑ́ς; τῆς ᾰ̓κτῖνος (Attic)

Case / #	Singular	Dual	Plural
Nominative	ἡ ᾰ̓κτῑ́ς hē ăktī́s	τὼ ᾰ̓κτῖνε tṑ ăktîne	αἱ ᾰ̓κτῖνες hai ăktînes
Genitive	τῆς ᾰ̓κτῖνος tês ăktînos	τοῖν ᾰ̓κτῑ́νοιν toîn ăktī́noin	τῶν ᾰ̓κτῑ́νων tôn ăktī́nōn
Dative	τῇ ᾰ̓κτῖνῐ tēî ăktînĭ	τοῖν ᾰ̓κτῑ́νοιν toîn ăktī́noin	ταῖς ᾰ̓κτῖσῐ / ᾰ̓κτῖσῐν taîs ăktîsĭ(n)
Accusative	τὴν ᾰ̓κτῖνᾰ tḕn ăktînă	τὼ ᾰ̓κτῖνε tṑ ăktîne	τᾱ̀ς ᾰ̓κτῖνᾰς tā̀s ăktînăs
Vocative	ᾰ̓κτῑ́ς ăktī́s	ᾰ̓κτῖνε ăktîne	ᾰ̓κτῖνες ăktînes
Notes:	This table gives Attic inflectional endings. For declension in other dialects, see Appendix:Ancient Greek dialectal declension.

Third declension of ᾰ̓κτῑ́ς; ᾰ̓κτῖνος (Epic)

Case / #	Singular	Dual	Plural
Nominative	ᾰ̓κτῑ́ς ăktī́s	ᾰ̓κτῖνε ăktîne	ᾰ̓κτῖνες ăktînes
Genitive	ᾰ̓κτῖνος ăktînos	ᾰ̓κτῑ́νοιν / ᾰ̓κτῑ́νοιῐν ăktī́noi(ĭ)n	ᾰ̓κτῑ́νων ăktī́nōn
Dative	ᾰ̓κτῖνῐ ăktînĭ	ᾰ̓κτῑ́νοιν / ᾰ̓κτῑ́νοιῐν ăktī́noi(ĭ)n	ᾰ̓κτῖσῐ / ᾰ̓κτῖσῐν / ᾰ̓κτῑ́νεσῐ / ᾰ̓κτῑ́νεσῐν / ᾰ̓κτῑ́νεσσῐ / ᾰ̓κτῑ́νεσσῐν ăktîsĭ(n) / ăktī́nesĭ(n) / ăktī́nessĭ(n)
Accusative	ᾰ̓κτῖνᾰ ăktînă	ᾰ̓κτῖνε ăktîne	ᾰ̓κτῖνᾰς ăktînăs
Vocative	ᾰ̓κτῑ́ς ăktī́s	ᾰ̓κτῖνε ăktîne	ᾰ̓κτῖνες ăktînes
Notes:	Dialects other than Attic are not well attested. Some forms may be based on conjecture. Use with caution.

^ Beekes, Robert S. P. (2010), “ἀκτίς, -ῖνος”, in Etymological Dictionary of Greek (Leiden Indo-European Etymological Dictionary Series; 10), with the assistance of Lucien van Beek, Leiden, Boston: Brill, →ISBN, pages 58–59
^ Mallory, J. P. with Adams, D. Q. (2006), The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World (Oxford Linguistics), New York: Oxford University Press, →ISBN, page 305

“ἀκτίς”, in Liddell & Scott (1940), A Greek–English Lexicon, Oxford: Clarendon Press
“ἀκτίς”, in Liddell & Scott (1889), An Intermediate Greek–English Lexicon, New York: Harper & Brothers
“ἀκτίς”, in Autenrieth, Georg (1891), A Homeric Dictionary for Schools and Colleges, New York: Harper and Brothers
ἀκτίς in Bailly, Anatole (1935), Le Grand Bailly: Dictionnaire grec-français, Paris: Hachette
ἀκτίς in Cunliffe, Richard J. (1924), A Lexicon of the Homeric Dialect: Expanded Edition, Norman: University of Oklahoma Press, published 1963
ἀκτίς in the Diccionario Griego–Español en línea (2006–2025)
“ἀκτίς”, in Slater, William J. (1969), Lexicon to Pindar, Berlin: Walter de Gruyter
Woodhouse, S. C. (1910), English–Greek Dictionary: A Vocabulary of the Attic Language‎^[1], London: Routledge & Kegan Paul Limited.
- beam idem, page 66.
- brightness idem, page 98.
- gleam idem, page 361.
- glimmer idem, page 362.
- ray idem, page 674.
- sunbeam idem, page 838.