A v. ξεῖ.
Ξ, ξ, ξῖ, τό, indecl., fourteenth letter of the Gk. alphabet: as numeral ξ# = 60, but #22ξ = 60, 000: introduced in the archonship of Euclides, 403 B. C.—It is a double consonant, compounded of γς, κς, or χς. Changes
1. ξ in aeolic and attic appears as an aspirated form of κ, cf. ξυνός with κοινός, ξύν with cum;— or of ς, cf. ξύν with σύν, ξέστης with Lat. sextarius; and so in doric fut. of Verbs in -ζω, κομίξω κλᾳξῶ παιξῶ for κομίσω κλῄσω παίσω.
2. interchanged with σς, ionic διξός, τριξός for δισσός, τρισσός.