Probably a loanword from a language from Asia Minor; compare Old Armenian կասկ (kask). Claimed by ancient writers to derive from Καστανέα (Kastanéa), a location in Asia Minor, but the location itself is most likely named after the tree.
- (5th BC Attic): IPA: /kástanon/
- (1st BC Egyptian): IPA: /kástanon/
- (4th AD Koine): IPA: /kástanon/
- (10th AD Byzantine): IPA: /kástanon/
- (15th AD Constantinopolitan): IPA: /kástanon/
Usually in plural. The singular is quite rare. Many of the Alternative forms are given in the plural (their only attested form).