Chi (upper case Χ, lower case χ) is the 22nd letter of the Greek alphabet. In the system of Greek numerals it has a value of 600. The 'ch' in 'chi' is a voiceless palatal fricative. In front of "light" vowels (e, i, oi, ai, y) it is prounounced like the 'ch' in German 'ich' or some variants of 'h' in the English 'hew' or 'human'. In front of "dark" vowels (a, o, ou) and of consonants, it is pronounced like the 'ch' in German 'ach' or in Scottish 'loch'. The Greek language is written in the Greek alphabet, developed in classical times (ca 9th century BC) and passed down to the present. ... Alpha (uppercase Α, lowercase α) is the first letter of the Greek alphabet. ... Beta (upper case Β, lower case β) is the 2nd letter of the Greek alphabet. ... Gamma (upper case Γ, lower case γ) is the 3rd letter of the Greek alphabet. ... Delta (upper case Δ, lower case δ) is the 4th letter of the Greek alphabet. ... Epsilon (upper case Ε, lower case ε) is the fifth letter of the Greek alphabet. ... Zeta (upper case Ζ, lower case ζ) is the sixth letter of the Greek alphabet. ... For other meanings of ETA, see ETA (disambig). ... Note: A theta probe is a device for measuring soil moisture Theta (upper case Θ, lower case θ) is the eighth letter of the Greek alphabet. ... Iota (upper case Ι, lower case ι) is the ninth letter of the Greek alphabet. ... Kappa (upper case Κ, lower case κ) is the tenth letter of the Greek alphabet. ... Lambda (upper case Λ, lower case λ) is the 11th letter of the Greek alphabet. ... Mu (upper case Μ, lower case μ) is the 12th letter of the Greek alphabet. ... Nu (upper case Ν, lower case ν) is the 13th letter of the Greek alphabet. ... Xi (upper case Ξ, lower case ξ) is the 14th letter of the Greek alphabet. ... Omicron (upper case Ο, lower case ο) is the 15th letter of the Greek alphabet. ... Pi (upper case Π, lower case π) is the 16th letter of the Greek alphabet. ... Rho (upper case Ρ, lower case ρ) is the 17th letter of the Greek alphabet. ... Sigma (upper case Σ, lower case σ, alternative ς) is the 18th letter of the Greek alphabet. ... Tau (upper case Τ, lower case τ) is the 19th letter of the Greek alphabet. ... Upsilon (upper case Υ, lower case υ) is the 20th letter of the Greek alphabet. ... Phi (upper case Φ, lower case φ or ϕ), pronounced fee or fie (depending on context and, often, personal inclination), is the 21st letter of the Greek alphabet. ... Psi (Ψ ψ) is the 23rd letter of the Greek alphabet and has a numeric value of 700. ... Omega (Ω ω) (literally, big O) is the 24th and last letter of the Greek alphabet. ... Digamma, or Wau, (upper case , lower case ) is an obsolete letter of the Greek alphabet. ... San was a letter of the Greek alphabet, between Pi and Qoppa, corresponding in position although not in name to the Phoenician tsade. ... Qoppa is an obsolete letter of the Greek alphabet and has a numeric value of 90. ... Sampi (Upper case Ϡ, lower case ϡ) is an obsolete letter of the Greek alphabet and has a numeric value of 900. ... The Greek language is written in the Greek alphabet, developed in classical times (ca 9th century BC) and passed down to the present. ... Greek numerals are a system of representing numbers using letters of the Greek alphabet. ... The voiceless palatal fricative is a type of consonantal sound, used in some spoken languages. ... The English language is a West Germanic language that originates in England. ...

The upper-case letter Χ is used as the symbol for:

• The name of Jesus Christ in Christianity, as in X-mas etc.

The lower-case letter χ is used as the symbol for: The neutrality and accuracy of this article are disputed. ... Christ, from the Greek in english known as Χριστός, or Khristós, means anointed, and is equivalent to the Hebrew term Messiah. ... Xmas is an abbreviation for Christmas. ...

• The chi-square distribution in statistics.
• The electric susceptibility (when a subscript e is present) and magnetic susceptibility in physics.
• The chromatic number and the chromatic index (when shown with a prime mark or a subscript 1) of a graph in graph theory.
• The Euler characteristic in algebraic topology.
• The voiceless uvular fricative (IPA) in phonology.

Chi is the basis for the name Chiastic structure and the name of Chiasmus. For any positive integer , the chi-square distribution with k degrees of freedom is the probability distribution of the random variable where are independent standard normal variables (zero expected value and unit variance). ... Statistics is the science and practice of developing knowledge through the use of empirical data expressed in quantitative form. ... The electric susceptibility χe is essentially the constant of proportionality (which may be a tensor) relating an applied electric field E to the induced dielectric polarisation P such that: Where ε0 is the electric permittivity of free space. ... In electrical engineering, the magnetic susceptibility is the degree of magnetization of a material in response to a magnetic field. ... Wikibooks Wikiversity has more about this subject: School of Physics sci. ... A 3_coloring suits this graph, but fewer colors would result in adjacent verticies of the same color. ... In graph theory, similar to its vertex counterpart, an edge coloring of a graph, when used without any qualification, is always assumed to be a proper coloring on the edges, meaning no two incident edges are assigned the same color. ... In mathematics and computer science, graph theory studies the properties of graphs. ... In algebraic topology, the Euler characteristic is a topological invariant (in fact, homotopy invariant) defined for a broad class of topological spaces. ... Algebraic topology is a branch of mathematics in which tools from abstract algebra are used to study topological spaces. ... The voiceless uvular fricative is a type of consonantal sound, used in some spoken languages. ... The International Phonetic Alphabet is a phonetic alphabet used by linguists to accurately and uniquely represent each of the wide variety of sounds (phones or phonemes) the human vocal apparatus can produce. ... Phonology (Greek phone = voice/sound and logos = word/speech), or phonemics, is a subfield of grammar (see also linguistics). ... Chiastic structure is a literary structure used most notably in the Torah. ... Chiasmus is a figure of speech based on inverted parallelism. ...