Chi (letter)
Encyclopedia
Chi is the 22nd letter of the Greek alphabet
, pronounced as ˈkaɪ in English.
was an aspirated velar stop
/kʰ/ (in the Western Greek alphabet: /ks/).
and later dialects it became a fricative
along with Θ and Φ
.
, it has two distinct pronunciations: In front of high
or front vowel
s (/e/ or /i/) it is pronounced as a voiceless palatal fricative
[ç], as in German
ich or like the h in some pronunciations of the English
words hew and human. In front of low
or back vowel
s (/a/, /o/ or /u/) and consonants, it is pronounced as a voiceless velar fricative
([x]), as in German ach. Chi is Romanized as in most systematic transliteration conventions, but also sometimes as or in informal practice.
used the chi instead of xi to represent the /ks/ sound. This was borrowed into the early Latin
language, which led to the letter X being used for the same sound in Latin, and the modern languages which use the Latin alphabet
.
as the letter Х
, with the phonetic value /x/ or /h/.
, chi is the symbol for the voiceless uvular fricative.
's Timaeus
, it is explained that the two bands which form the soul of the world
cross each other like the letter Χ.
Chi or X
is often used to abbreviate the name Christ, as in the holiday Christmas
(Xmas
). When fused within a single typespace with the Greek letter Rho
, it is called the labarum
and used to represent the person of Jesus Christ.
is also frequently used in statistics
.
In Algebraic Topology
, Chi is used to represent the Euler Characteristic
of a surface.
The optic chiasm
, an x-shaped connection of the optic nerves leading to the eye, got its name from the letter chi because of its shape; likewise, the shape of the letter chi is the origin of the rhetorical device
chiasmus
.
In EN 1993
, an European Standard for the design of steel structures, the chi character is used as a symbol for the reduction factor for the relevant buckling
load.
Greek alphabet
The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...
, pronounced as ˈkaɪ in English.
Greek
Ancient Greek
Its value in Ancient GreekAncient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
was an aspirated velar stop
Voiceless velar plosive
The voiceless velar stop or voiceless velar plosive is a type of consonantal sound used in many spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is , and the equivalent X-SAMPA symbol is k....
/kʰ/ (in the Western Greek alphabet: /ks/).
Koine Greek
In Koine GreekKoine Greek
Koine Greek is the universal dialect of the Greek language spoken throughout post-Classical antiquity , developing from the Attic dialect, with admixture of elements especially from Ionic....
and later dialects it became a fricative
Fricative consonant
Fricatives are consonants produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate, in the case of German , the final consonant of Bach; or...
along with Θ and Φ
Phi (letter)
Phi , pronounced or sometimes in English, and in modern Greek, is the 21st letter of the Greek alphabet. In modern Greek, it represents , a voiceless labiodental fricative. In Ancient Greek it represented , an aspirated voiceless bilabial plosive...
.
Modern Greek
In Modern GreekModern Greek
Modern Greek refers to the varieties of the Greek language spoken in the modern era. The beginning of the "modern" period of the language is often symbolically assigned to the fall of the Byzantine Empire in 1453, even though that date marks no clear linguistic boundary and many characteristic...
, it has two distinct pronunciations: In front of high
Close vowel
A close vowel is a type of vowel sound used in many spoken languages. The defining characteristic of a close vowel is that the tongue is positioned as close as possible to the roof of the mouth without creating a constriction that would be classified as a consonant.This term is prescribed by the...
or front vowel
Front vowel
A front vowel is a type of vowel sound used in some spoken languages. The defining characteristic of a front vowel is that the tongue is positioned as far in front as possible in the mouth without creating a constriction that would be classified as a consonant. Front vowels are sometimes also...
s (/e/ or /i/) it is pronounced as a voiceless palatal fricative
Voiceless palatal fricative
The voiceless palatal fricative is a type of consonantal sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is . The symbol ç is the letter c with a cedilla, as used to spell French words such as façade...
[ç], as in German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
ich or like the h in some pronunciations of the English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
words hew and human. In front of low
Open vowel
An open vowel is defined as a vowel sound in which the tongue is positioned as far as possible from the roof of the mouth. Open vowels are sometimes also called low vowels in reference to the low position of the tongue...
or back vowel
Back vowel
A back vowel is a type of vowel sound used in spoken languages. The defining characteristic of a back vowel is that the tongue is positioned as far back as possible in the mouth without creating a constriction that would be classified as a consonant. Back vowels are sometimes also called dark...
s (/a/, /o/ or /u/) and consonants, it is pronounced as a voiceless velar fricative
Voiceless velar fricative
The voiceless velar fricative is a type of consonantal sound used in some spoken languages. The sound was part of the consonant inventory of Old English and can still be found in some dialects of English, most notably in Scottish English....
([x]), as in German ach. Chi is Romanized as
Xi
In ancient times, some local forms of the Greek alphabetGreek alphabet
The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...
used the chi instead of xi to represent the /ks/ sound. This was borrowed into the early Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
language, which led to the letter X being used for the same sound in Latin, and the modern languages which use the Latin alphabet
Latin alphabet
The Latin alphabet, also called the Roman alphabet, is the most recognized alphabet used in the world today. It evolved from a western variety of the Greek alphabet called the Cumaean alphabet, which was adopted and modified by the Etruscans who ruled early Rome...
.
Cyrillic
Chi was also included in the Cyrillic alphabetCyrillic alphabet
The Cyrillic script or azbuka is an alphabetic writing system developed in the First Bulgarian Empire during the 10th century AD at the Preslav Literary School...
as the letter Х
Kha
Kha or Ha is a letter of the Cyrillic alphabet.It commonly represents the voiceless velar fricative , like the Scottish pronunciation of ⟨ch⟩ in "loch".Kha is romanized as ⟨kh⟩.-History:...
, with the phonetic value /x/ or /h/.
International Phonetic Alphabet
In the International Phonetic AlphabetInternational Phonetic Alphabet
The International Phonetic Alphabet "The acronym 'IPA' strictly refers [...] to the 'International Phonetic Association'. But it is now such a common practice to use the acronym also to refer to the alphabet itself that resistance seems pedantic...
, chi is the symbol for the voiceless uvular fricative.
Symbolism
In PlatoPlato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
's Timaeus
Timaeus (dialogue)
Timaeus is one of Plato's dialogues, mostly in the form of a long monologue given by the title character, written circa 360 BC. The work puts forward speculation on the nature of the physical world and human beings. It is followed by the dialogue Critias.Speakers of the dialogue are Socrates,...
, it is explained that the two bands which form the soul of the world
Anima mundi (spirit)
The world soul is, according to several systems of thought, an intrinsic connection between all living things on the planet, which relates to our world in much the same way as the soul is connected to the human body...
cross each other like the letter Χ.
Chi or X
X
X is the twenty-fourth letter in the basic modern Latin alphabet.-Uses:In mathematics, x is commonly used as the name for an independent variable or unknown value. The usage of x to represent an independent or unknown variable can be traced back to the Arabic word šay شيء = “thing,” used in Arabic...
is often used to abbreviate the name Christ, as in the holiday Christmas
Christmas
Christmas or Christmas Day is an annual holiday generally celebrated on December 25 by billions of people around the world. It is a Christian feast that commemorates the birth of Jesus Christ, liturgically closing the Advent season and initiating the season of Christmastide, which lasts twelve days...
(Xmas
Xmas
"Xmas" is a common abbreviation of the word "Christmas". It is sometimes pronounced , but it, and variants such as "Xtemass", originated as handwriting abbreviations for the typical pronunciation...
). When fused within a single typespace with the Greek letter Rho
Rho (letter)
Rho is the 17th letter of the Greek alphabet. In the system of Greek numerals, it has a value of 100. It is derived from Semitic resh "head"...
, it is called the labarum
Labarum
The labarum was a vexillum that displayed the "Chi-Rho" symbol ☧, formed from the first two Greek letters of the word "Christ" — Chi and Rho . It was used by the Roman emperor Constantine I...
and used to represent the person of Jesus Christ.
Math and science
ChiChi-squared
In statistics, the term chi-squared has different uses:*chi-squared distribution, a continuous probability distribution;*chi-squared statistic, a statistic used in some statistical tests;...
is also frequently used in statistics
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
.
In Algebraic Topology
Algebraic topology
Algebraic topology is a branch of mathematics which uses tools from abstract algebra to study topological spaces. The basic goal is to find algebraic invariants that classify topological spaces up to homeomorphism, though usually most classify up to homotopy equivalence.Although algebraic topology...
, Chi is used to represent the Euler Characteristic
Euler characteristic
In mathematics, and more specifically in algebraic topology and polyhedral combinatorics, the Euler characteristic is a topological invariant, a number that describes a topological space's shape or structure regardless of the way it is bent...
of a surface.
The optic chiasm
Optic chiasm
The optic chiasm or optic chiasma is the part of the brain where the optic nerves partially cross...
, an x-shaped connection of the optic nerves leading to the eye, got its name from the letter chi because of its shape; likewise, the shape of the letter chi is the origin of the rhetorical device
Rhetorical device
In rhetoric, a rhetorical device or resource of language is a technique that an author or speaker uses to convey to the listener or reader a meaning with the goal of persuading him or her towards considering a topic from a different perspective. While rhetorical devices may be used to evoke an...
chiasmus
Chiasmus
In rhetoric, chiasmus is the figure of speech in which two or more clauses are related to each other through a reversal of structures in order to make a larger point; that is, the clauses display inverted parallelism...
.
In EN 1993
EN 1993
EN 1993 - Eurocode 3: Design of steel structures, is the part of the European building code that deals with the design of steel structures, using the limit state design philosophy...
, an European Standard for the design of steel structures, the chi character is used as a symbol for the reduction factor for the relevant buckling
Buckling
In science, buckling is a mathematical instability, leading to a failure mode.Theoretically, buckling is caused by a bifurcation in the solution to the equations of static equilibrium...
load.