From Proto-Indo-European *ḱwṓ. Cognates include Latin canis, Sanskrit श्वन् (śván) and Old English hund (English hound). The final -ν (-n) in the nominative singular which was absent in *ḱwṓ was restored in Greek by analogy to other forms in the paradigm.
- (5th BC Attic): IPA: /ký.ɔ͜ɔn/
- (1st BC Egyptian): IPA: /kýoːn/
- (4th AD Koine): IPA: /kýon/
- (10th AD Byzantine): IPA: /cýon/
- (15th AD Constantinopolitan): IPA: /cíon/
- The alternate forms κύων (vocative singular) and κύνεσσι (dative plural) also exist.