Of Pre-Greek origin (acc. to Frisk), possibly from Egyptian *kai 'other' (in writing ky, becoming ke in Sahidic), developing a sense of 'also' by Late Egyptian. A link with Proto-Indo-European conjunctive particle *kʷe 'and' (> Latin -que) is impossible on phonetic grounds.
- (5th BC Attic): IPA: /kă͜ɪ̆́/
- (1st BC Egyptian): IPA: /kɛ/
- (4th AD Koine): IPA: /ke/
- (10th AD Byzantine): IPA: /ce/
- (15th AD Constantinopolitan): IPA: /ce/
- και (kai, “and”)