- Psi (letter)
:"For other uses, see
Psi."Psi (uppercase Ψ, lowercase ψ) is the 23rd letter of the Greek alphabetand has a numeric value of 700. In both Classical and Modern Greek, the letter indicates the combination /ps/ (like in English "lapse"). In Greek, this consonant cluster can occur in the syllable initial position, as in the Greek word "ψάρι" [psári (=fish)] . However, in some languages (including English) this combination is not possible at the beginning of a syllable. In Latin, Greek words beginning with psi are transcribed by "ps-", but seem to have been pronounced simply as "s-", with a quiescent "p".Fact|date=May 2007 This pronunciation has affected that of Greek loanwords beginning with the letter in several languages. In English, for example, "psychology" is pronounced with a silent "p", and the name of the letter is often pronounced IPA| [saɪ] ("sigh"), although this is not always the case. The letter was adopted into the Old Italic alphabet, and its shape is continued into the Algizrune of the Elder Futhark.
The letter may have originated from the practice of writing the
sigmaover the pi, eventually making the combination into a single letter.Fact|date=November 2007 Psi was also adopted into the early Cyrillic alphabet. See psi (Cyrillic)(Unicode|Ѱ, Unicode|ѱ). This may have also been since the letter, both in lower case and uppercase form, resembles the tridentwielded by Poseidon, the Greek god of water/ocean.
The letter psi is commonly used in
physicsfor representing a wavefunctionin quantum mechanics, particularly with the Schrödinger equationand bra-ket notation: . It is also used to represent the (generalized) positional states of a qubitin a quantum computer.
Psi is also used as the symbol for the
polygamma function, defined by:where is the gamma function.
The letters Ψ or ψ can also be a symbol for:
psychology, psychiatry, and sometimes parapsychology(involving paranormalor relating with the supernaturalsubjects).
*In mathematics, the number of the "Supergolden Ratio", approximately 1.4 and the solution to the cubic equation x³ = x² + 1.
Water potentialin movement of water between plant cells.
Stream functionin fluid mechanicsdefining the curve to which the flow velocityis always tangent.
*One of the
dihedral angles in the backbones of proteins
Schrodinger Equationand throughout quantum mechanics, ψ(x) stands for the wave function
Indiana University(as a superimposed Iand U)
*A Sai, the name of which is pronounced the same way.
Pharmacology, general pharmacy
virologythe ψ site is a viral packaging signal.
J/ψmeson, in particle physics.
*In the manga
Monochrome, Psi is a mentally disturbed character, though her name is usually spelled out.
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Psi — may refer to:As a word* Psi (Greek) (Ψ, ψ) a letter of the Greek alphabet * Psi (Cyrillic) (Ѱ, ѱ), a letter of the early Cyrillic alphabet, adopted from Greek * Psi (instant messaging client), a popular Jabber client program * Psi… … Wikipedia
Psi (Buchstabe) — Psi Das Psi (griechisches Neutrum Ψι, Majuskel Ψ, Minuskel ψ) ist der 23. Buchstabe des griechischen Alphabets und hat nach dem milesischen Prinzip einen numerischen Wert von 700. Verwendung Psi ist das Symbol der Psychologie. In … Deutsch Wikipedia
PSI Logistics — GmbH Год основания 2001 Расположение … Википедия
Psi Islands — (coord|64|18|S|63|1|W|) is a group of small islands which lie close to the west side of Lambda Island in the Melchior Islands, Palmer Archipelago. The name, derived from the 23rd letter of the Greek alphabet, appears to have been first used on a… … Wikipedia
psi — 23rd letter of the Greek alphabet. Use for psychic force, paranormal phenomenon dates from 1942 … Etymology dictionary
psi — ► NOUN 1) the twenty third letter of the Greek alphabet ( , ), transliterated as ‘ps’. 2) supposed psychic faculties or phenomena. ORIGIN Greek … English terms dictionary
psi — psi1 [sī, psē] n. [LGr < Gr psei] the twenty third letter of the Greek alphabet (Ψ, ψ) psi2 [sī] adj. of or having to do with psychic or paranormal abilities or phenomena n. such abilities or phenomena collectively psi3 abbrev. pounds per… … English World dictionary
Psi (lettre grecque) — Pour les articles homonymes, voir Psi, Psy et PSI. Psi Graphies Ca … Wikipédia en Français
Psi (Cyrillic) — Cyrillic alphabet navbox Heading=Cyrillic letter Psi uuc=0470|ulc=0471|numeral=700Psi (Ѱ, ѱ) is a letter in the early Cyrillic alphabet, derived from the Greek letter psi (Ψ, ψ). It represents the sound /ps/, as in English naps , and was used… … Wikipedia
Psi (instant messaging client) — Infobox Software name = Psi caption = Psi 0.11 collapsible = yes developer = The Psi Team released = July 7th 2001 [ [http://web.archive.org/web/20011218061414/www.affinix.com/ justin/ http://www.affinix.com/ justin Archive.org] ] frequently… … Wikipedia