abbr.
pounds per square inch
| Dictionary: psi3 |
| Abbreviations: PSI |
| Meaning | Category |
| Packetnet System Interface | Computing->Networking |
| Pain, Spasm, and Inflammation | Medical->Physiology |
| Parapsychology Studies Institute | Academic & Science->Universities |
| Partai Sosialis Indonesia | International->Indonesian |
| Partido Socialista Interior | International->Spanish |
| Pasni, Pakistan | Regional->Airport Codes |
| Peer Search Infrastructure | Business->Positions |
| People Synergistically Involved | Community |
| Personalized System of Instruction | Academic & Science->Universities |
| Pharmaceutical Society of Ireland | Medical->Veterinary |
| Pharmacy Service Initiative | Medical->Hospitals |
| Pleural Space Infection | Medical->Physiology |
| Poetry Slam Incorporated | Community->Non-Profit Organizations |
| Pollution Standard Index | Academic & Science->Meteorology Governmental->US Government |
| Porta Systems Corporation | Business->AMEX Symbols |
| Position Specific Iterated | Academic & Science->Mathematics |
| Post Secondary Institution | Academic & Science->Universities |
| Post Shipment Inspection | Governmental->Transportation |
| Postponing Sexual Involvement | Community->Educational |
| Potential Security Informant | Governmental->FBI Files |
| Pounds per Square Inch | Academic & Science->Chemistry Academic & Science->Electronics Governmental->Military Academic & Science->Ocean Science Academic & Science->Physics Governmental->Transportation Miscellaneous->Unit Measures |
| Power Static Inverter | Governmental->NASA |
| Pre-Sentence Investigation | Community->Law |
| Precise Stylus Input | Computing->General |
| Present Serviceability Index | Governmental->Transportation |
| Pressure Stuck Inside | Miscellaneous->Funnies |
| Pressure Systems Incorporated | Business->Firms |
| Probability, Statistics, and Inference | Academic & Science->Universities |
| Products, Services, and Ideas | Business->General |
| Professional Service Industries | Business->Firms |
| Protein Structure Initiative | Medical->Laboratory |
| Provider of Statistical Information | Business->General |
| Psychological Society of Ireland | Community->Non-Profit Organizations |
| Psychology Slander Intuition | Academic & Science->Universities |
| Psychology Student Instructor | Academic & Science->Universities |
| Public Subject Identifiers | Governmental->US Government |
| Published Subject Identifier | Community->Media |
| Pure Style Incorporated | Business->Firms |
| Pusat Sumber Ilmu | Business->International Business |
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| WordNet: psi |
The noun has 2 meanings:
Meaning #1:
a unit of pressure
Synonym: pounds per square inch
Meaning #2:
the 23rd letter of the Greek alphabet
| Wikipedia: Psi (letter) |
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| Look up Ψ or ψ in Wiktionary, the free dictionary. |
| Greek alphabet | |||
|---|---|---|---|
| Αα | Alpha | Νν | Nu |
| Ββ | Beta | Ξξ | Xi |
| Γγ | Gamma | Οο | Omicron |
| Δδ | Delta | Ππ | Pi |
| Εε | Epsilon | Ρρ | Rho |
| Ζζ | Zeta | Σσς | Sigma |
| Ηη | Eta | Ττ | Tau |
| Θθ | Theta | Υυ | Upsilon |
| Ιι | Iota | Φφ | Phi |
| Κκ | Kappa | Χχ | Chi |
| Λλ | Lambda | Ψψ | Psi |
| Μμ | Mu | Ωω | Omega |
| Obsolete letters | |||
| Digamma | Qoppa | ||
| San | Sampi | ||
| Other characters | |||
| Stigma | Sho | ||
| Heta | |||
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| Greek diacritics | |||
Psi (uppercase Ψ, lowercase ψ; pronounced sigh) is the 23rd letter of the Greek alphabet and has a numeric value of 700. In both Classical and Modern Greek, the letter indicates the combination /ps/ (like in English "lapse"). The letter was adopted into the Old Italic alphabet, and its shape is continued into the Algiz rune of the Elder Futhark. Psi was also adopted into the early Cyrillic alphabet as Ѱ. In Greek loanwords in Latin and modern languages with Latin alphabets, Psi is usually transliterated as "ps". In English, due to phonotactic constraints, its pronunciation is usually simplified to /s/.
The letter psi is commonly used in physics for representing a wavefunction in quantum mechanics, particularly with the Schrödinger equation and bra-ket notation:
. It is also used to represent the (generalized) positional states of a qubit in a quantum computer.
Psi is also used as the symbol for the polygamma function, defined by

where Γ(x) is the gamma function.
The letters Ψ or ψ can also be a symbol for:
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
| Shopping: Psi |
| Psi Research (parapsychology) | |
| Psi-Conducive (parapsychology) | |
| Psi-Inhibiting (parapsychology) |
Copyrights:
![]() | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more | |
![]() | Abbreviations. STANDS4.com - The source for acronyms and abbreviations. Copyright ©2004-2007 STANDS4 LLC. All rights reserved. Read more | |
![]() | WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. Read more | |
![]() | Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Psi (letter)". Read more |
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