Chi (letter)

==Greek==
[[File:NAMA Alphabet grec.jpg|thumb|The Greek alphabet on a [[black figure]] vessel, with a cross-shaped chi]]

===Pronunciation===
====Ancient Greek====
Its value in [[Ancient Greek]] was an aspirated [[voiceless velar plosive|velar stop]] {{IPA|/kʰ/}} (in the [[Western Greek alphabet]]: /ks/).

====Koine Greek====
In [[Koine Greek]] and later dialects it became a [[Fricative consonant|fricative]] ({{IPA|[x]}}/{{IPA|[ç]}}) along with [[Theta (letter)|Θ]] and [[Phi (letter)|Φ]].

====Modern Greek====
In [[Modern Greek]], it has two distinct pronunciations: In front of [[close vowel|high]] or [[front vowel]]s ({{IPA|/e/}} or {{IPA|/i/}}) it is pronounced as a [[voiceless palatal fricative]] {{IPA|[ç]}}, as in [[Standard German phonology#Ich-Laut and ach-Laut|German ''ich'']] or like [[English phonology#Consonants|some pronunciations of "h"]] in English words like ''hew'' and ''human''. In front of [[open vowel|low]] or [[back vowel]]s ({{IPA|/a/}}, {{IPA|/o/}} or {{IPA|/u/}}) and [[consonants]], it is pronounced as a [[voiceless velar fricative]] ({{IPA|[x]}}), as in German ''ach'' or [[Spanish phonology#Consonants|Spanish ''j'']]. This distinction corresponds to the ich-Laut and ach-Laut of German.

===Transliteration===
Chi is [[Romanization of Greek|romanized]] as {{angle bracket|ch}} in most systematic transliteration conventions, but sometimes {{angle bracket|kh}} is used.<ref>[https://www.britannica.com/EBchecked/topic/3390/Achaea Encyclopædia Britannica]</ref> In addition, in Modern Greek, it is often also romanized as {{angle bracket|h}} or {{angle bracket|x}} in informal practice.

===Greek numeral===
In the system of [[Greek numerals]], it has a value of 600.

===Xi===
In ancient times, some [[History of the Greek alphabet#Epichoric alphabets|local forms]] of the [[Greek alphabet]] used the chi instead of [[Xi (letter)|xi]] to represent the /ks/ sound. This was borrowed into the early [[Latin]] language, which led to the use of the letter X for the same sound in Latin, and many modern languages that use the [[Latin alphabet]].