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
Greek alphabet the abjads used in Semitic languages, which have letters only for consonants. Greek initially took over all of the 22 letters of Phoenician. Five were reassigned to denote vowel sounds: the glide consonants ("yodh") and ("waw") were used for [i] (Ι, "iota") and [u] (Υ, "upsilon") respectively; the glottal stop consonant ("|aleph") was used for [a] (Α, "alpha"); the pharyngeal ("ʿayin") was turned into [o] (Ο, "omicron"); and the letter for ("he") was turned into [e] (Ε, "epsilon"). A doublet of waw was also borrowed as a consonant for [w] (Ϝ, digamma). In addition, the Phoenician letter for the emphatic