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
History of the Greek alphabet Often, in medieval manuscripts, old uncial letter forms were mixed in with the normal minuscule letters for writing titles or for emphasizing the initial letter of a word or sentence. Like in Latin, this became the root of the modern innovation of letter case, the systematic distinction between uppercase and lowercase letters in orthography. The uppercase letters of modern orthography are derived from the uncial script, while the lowercase letters are derived from minuscules. The invention of printing saw the codification of a more fixed set of letter structures. Greek handwriting made extensive use of ligatures with letters written differently