xi English · revision 7632

+ {{infobox|confidence=established|formation=borrowing|attested=early 15th century|origins=grc ξῖ}}

+

+ ==Pronunciation==

+ * IPA: /zaɪ/, /saɪ/^(Wiktionary)

+

+ ==Etymology==

+ It is [[bor|grc|ξῖ|tr=xî]], the name of the fourteenth letter of the Greek alphabet.^(Etymonline)^(MWU 2024)^(NODE 1998)

+

+ ==Earliest recorded meaning==

+ The Greek letter: by the early 15th century in Etymonline, the 15th century in MWU.^(Etymonline)^(MWU 2024)

+

+ ==Semantic evolution==

+ In physics, either of a pair of hyperons, the xi particles, is from 1954.^(OED 1989)^(AHD)

+

+ ==Timeline==

+ * early 15th century – the Greek letter.^(Etymonline)

+ * 1954 – the xi particle.^(OED 1989)

+

+ ==Modern meaning==

+ ===Noun===

+ # The fourteenth [[letter]] of the Greek [[alphabet]] (Ξ, ξ), transliterated as x.^(AHD)^(Collins 2023)

+ # ''(physics)'' A xi [[hyperon]].^(AHD)^(OED 1989)

+

+ ==Related words==

+ * [[xenon]]

+ * [[alphabet]]

+

+ ==Usage notes==

+ Collins gives several pronunciations: /zaɪ/, /saɪ/, /ksaɪ/ and /ksiː/.^(Collins 2023) The Xi is also a river of southern China.^(Collins 2023)

+

+ ==References==

+ {{reflist}}