Word.ws English Dictionary

psi

/psaɪ/

psi noun: the twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek.

psi: the twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and...
Image: Mrmw, Fred the Oyster, Public domain, via Wikimedia Commons

Noun (1)

psi (countable and uncountable, plural psis)

  1. (countable) The twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek.
  2. (uncountable) A form of psychic energy.
    • ‘Come, lad,’ he said. ‘We will take tea together and speak of the noumenon, the psi and other more heterogenous phenomena.’1993, Will Self, My Idea of Fun
    • When an event is classified as a psi phenomenon, it is claimed that all known channels for the apparent interaction have been eliminated.1996, Michael F. Stoeber, Hugo Anthony Meynell, Critical Reflections on the Paranormal (page 60)

Symbol

psi

  1. Pound per square inch (an imperial unit of pressure)
    • Each turbogenerator consisted of a steam turbine, powered by 900 psi of superheated steam, that was coupled by a set of reduction gears to a General Electric marine alternating-current generator operating at 1,800 rpm. Each generator had a capacity of 2,000 kilowatts of three-phase power at 450...2017 December 12, National Transportation Safety Board, “1.3.5 Electrical Generation and Distribution System”, in Marine Accident Report: Sinking of US Cargo Vessel SS El Faro, Atlantic Ocean...
    • For M2, this is typically around 3250 MPa (471,000 psi) when tempered at 300°F (149°C).2024 March 23, “Yield Strength of Steel: A Comprehensive Guide”, in Unionfab, archived from the original on 13 Jan 2026

Noun (2) capitalized: PSI

PSI

  1. (abbreviation, initialism) Initialism of pre-sentence investigation.
  2. (abbreviation, initialism) Initialism of protein structure initiative.
  3. (abbreviation, initialism) Initialism of pollutant safety/standard index (measurement of the air pollutant such as haze).

Proper noun capitalized: PSI

PSI

  1. (UK, abbreviation, initialism) Initialism of Policy Studies Institute, a British think tank.

psi meaning in Hindi, Tamil, Marathi and Urdu

psi in Hindi

पी. एस. आई, पीएसआई, पी. एस. आइ

psi in Tamil

பி. எஸ். ஐ, பிஎஸ்ஐ

psi in Marathi

पी. एस. आय, पीएसआय, पी. एस. आई

psi in Urdu

پی ایس آئی, پی۔ ایس۔ آئی
More languagesFewer languages
psi in Bengali
পি. এস. আই, পিএসআই
psi in Telugu
పిఎస్ఐ, పి. ఎస్. ఐ
psi in Malayalam
പി. എസ്. ഐ, പിഎസ്ഐ
psi in Kannada
ಪಿಎಸ್ಐ, ಪಿ. ಎಸ್. ಐ
psi in Punjabi
ਪੀ. ਐੱਸ. ਆਈ, ਪੀ. ਐਸ. ਆਈ
psi in Gujarati
પી. એસ. આઈ, પીએસઆઈ, પી. એસ. આઇ
psi in Odia
ପି. ଏସ୍. ଆଇ, ପି. ଏସ. ଆଇ, ପିଏସଆଇ
psi in Nepali
पीएसआई, पिएसआई
psi in Arabic
پْسِي psī, بْسِي bsī
psi in Malay
psi
psi in Persian
سای

Examples of psi in a sentence

  • If the air pressure drops below 60 psi, the signal arm will drop down across the windshield.
  • In our telekinesis case, the psi. might pick up microkinesis or macrokinesis at a certain level.
  • You can't reset it (push it back out of view) until air pressure is brought above 60 psi.

All 11 example sentences with psi

Forms of psi

Noun
pluralpsis
Symbol
alternative formP.S.I.
alternative formPSI

Plural of psi: psis

Origin of psi

From Middle English psi, from Latin psī, from Ancient Greek ψεῖ (pseî), the name for the twenty-third letter of the alphabet (Ψ, ψ).

Initialism of pounds per square inch.

Words formed from psi

Phrases with psi

Words that rhyme with psi

48 more rhymesFewer rhymes

Questions about psi

What does psi mean?
Psi means the twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek.
What is psi in Hindi?
Psi in Hindi is पी. एस. आई, पीएसआई, पी. एस. आइ. See Psi meaning in Hindi.
What part of speech is psi?
Psi can be a noun, a symbol or a proper noun.
How do you pronounce psi?
Psi is pronounced /psaɪ/.
What is the plural of psi?
The plural of psi is psis.

Words near psi in the dictionary

  1. pshht
  2. pshRNA
  3. pshRNAs
  4. PSHS
  5. psht
  6. psi
  7. psi function
  8. psi functions
  9. psi particle
  10. psi particles
  11. psia

Source and license

Adapted from Wiktionary: psi (page history and authors); PSI (page history and authors); psi (Hindi, IndicTrans2 machine translation) (model and license); psi (Tamil, IndicTrans2 machine translation) (model and license); psi (Marathi, IndicTrans2 machine translation) (model and license); psi (Urdu, IndicTrans2 machine translation) (model and license); psi (Bengali, IndicTrans2 machine translation) (model and license); psi (Telugu, IndicTrans2 machine translation) (model and license); psi (Malayalam, IndicTrans2 machine translation) (model and license); psi (Kannada, IndicTrans2 machine translation) (model and license); psi (Punjabi, IndicTrans2 machine translation) (model and license); psi (Gujarati, IndicTrans2 machine translation) (model and license); psi (Odia, IndicTrans2 machine translation) (model and license); psi (Nepali, IndicTrans2 machine translation) (model and license). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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Pronunciation audio from Wikimedia Commons, each file under its own free license: en-us-psi.ogg.

Cite this entry: “psi.” Word.ws, https://word.ws/psi. Based on Wiktionary, CC BY-SA 4.0.