ψεῖ
From LSJ
Ὦ τύμβος, ὦ νυμφεῖον, ὦ κατασκαφὴς οἴκησις αἰείφρουρος, οἷ πορεύομαι πρὸς τοὺς ἐμαυτῆς → Tomb, bridal chamber, eternal prison in the caverned rock, whither I go to find mine own.
English (LSJ)
τό, name of the letter ψ, Hellad. ap. Phot.Bibl.p.530 B.
Dutch (Woordenboekgrieks.nl)
ψεῖ, τό, ook ψῖ [~ πεῖ, πῖ] indecl. psi, drieëntwintigste letter van het alfabet.