Xi (letter) dialects of most of the Greek mainland and Euboea, the sound [ks] was represented by Χ (which in classical Greek is chi, used for ). Because this variant of the Greek alphabet was used in Italy, the Latin alphabet borrowed Χ rather than Ξ as the Latin letter X. While having no Latin derivative, the Xi was adopted into the early Cyrillic alphabet, as the letter ksi (Ѯ, ѯ). The uppercase letter Ξ is used as symbol for: The lowercase letter ξ is used as a symbol for: These characters are used only as mathematical symbols. Stylized Greek text should
Greek alphabet the Thirty Tyrants. Because of Eucleides's role in suggesting the idea to adopt the Ionian alphabet, the standard twenty-four-letter Greek alphabet is sometimes known as the "Eucleidean alphabet". Roughly thirty years later, the Eucleidean alphabet was adopted in Boeotia and it may have been adopted a few years previously in Macedonia. By the end of the fourth century BC, it had displaced local alphabets across the Greek-speaking world to become the standard form of the Greek alphabet. When the Greeks adapted the Phoenician alphabet, they took over not only the letter shapes and sound values, but also the names by