Stigma (letter) sigma form ς never occurs inside a word and is never used as a numeral either. Uppercase forms of stigma as a numeral (Ϛ) are rare in practice; when they occur, they can often be confused with uppercase forms of another numeral symbol, koppa (Ϟϟ), which stands for 90. Stigma is encoded in Unicode as "Greek letter stigma" U+03DA (Ϛ) and "Greek small letter stigma" U+03DB (ϛ). Stigma (letter) Stigma (ϛ) is a ligature of the Greek letters sigma (Σ) and tau (Τ), which was used in writing Greek between the Middle Ages and the 19th century. It is also
Nu (letter) Nu (letter) Nu (; uppercase Ν lowercase ν; "ni" ) or ny is the 13th letter of the Greek alphabet. In the system of Greek numerals it has a value of 50. It is derived from the ancient Phoenician language nun . Its Latin equivalent is N, though the lowercase resembles the Roman lowercase v (formula_1). The name of the letter is written in Ancient Greek and traditional Modern Greek polytonic orthography, while in Modern Greek it is written . The uppercase Nu is not used, because it is normally identical to Latin N. The lower-case letter ν is used