U+039E "Ξ" Greek Capital Letter Xi Unicode Character

U+039E "Ξ" Greek Capital Letter Xi is the uppercase form of the fourteenth letter in the Greek alphabet, derived from the Phoenician letter samekh. In ancient Greek, it represented the voiceless velar fricative /ks/ sound, a role it retains in modern Greek transcription. Beyond its linguistic function, this symbol is widely used in mathematics and science to denote the xi function in number theory and Riemann zeta function studies, as well as in particle physics for certain baryons. In typography, it appears as a distinctive three horizontal strokes character, often confused with the Cyrillic letter "З" or the lowercase xi "ξ" when capitalisation is overlooked. Its numeric value in the Greek numeral system is 60, and it is encoded in Unicode under the Greek and Coptic block.