ζ
From LSJ
δὶς ἐξαμαρτεῖν ταὐτὸν οὐκ ἀνδρὸς σοφοῦ → a wise man should not keep making the same mistake, a wise man should not repeat the same mistake, doing twice the same mistake is not a wise man's doing, making the same mistake twice does not befit the wise, making the same mistake twice does not belong to a man who is wise, making the same mistake twice does not belong to a wise man, the wise man does not make the same mistake twice, to commit the same sin twice is not a sign of a wise man, it is unwise to err twice
Russian (Dvoretsky)
ζ: (τό ζῆτα) дзета (6-я буква греч. алфавита); ζʹ = 7, ͵ζ = 7000 (число 6 обозначается вышедшей из употребления буквой Ϛ).
