What does "psi" mean?
The twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek.
Psi
/psaɪ/ name, noun, symbol
name, noun, symbol ·Uncommon ·Advanced level
Meaning at a glance
- Primary sense: The twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek.
- Grammar: psi is listed as name, noun, symbol.
- Nearest alternatives: greek letter, letter, paranormal ability, pounds per square inch.
- Useful contrasts: dimensionless quantity, normal perception.
- Usage evidence: The recommended tyre pressure of the average car is around 32 psi.
How to use "psi"
- Start with the primary definition, then check the part of speech before placing the word in a sentence.
- Compare nearby synonyms to make sure "psi" carries the exact meaning, tone, and strength you need.
- Use the example sentence as a context check. If your sentence uses the word differently, confirm that the grammar still fits.
Meaning check
- Does the word fit the sentence's grammar?
- Does it match the intended tone rather than only the dictionary definition?
- Would a simpler synonym be clearer for the reader?
- Is there enough surrounding context to prevent ambiguity?
Source and review context
This entry combines structured lexical data with WordToolSet review checks. Definitions, examples, synonyms, and usage notes may come from different source tables, so the page is designed to show evidence from more than one angle before you rely on "psi" in a final draft.
If a word has several senses, prefer the sense that matches your sentence's grammar and surrounding context. A correct definition can still be the wrong choice when the sentence needs a different register, emphasis, or level of specificity.
Before you rely on this definition
Read the first definition as a starting point, then check the example, synonyms, and part of speech before treating "psi" as the right word for your sentence.
If your draft is formal, technical, persuasive, or sensitive, compare "psi" with a nearby alternative so the final choice matches both meaning and reader expectation.
Compare nearby meanings
- Use synonyms when you need a softer, stronger, simpler, or more specific word.
- Use antonyms to check the boundary of the meaning and avoid accidental contrast.
- Use the example sentence to confirm the word behaves naturally in context.
- Keep the original wording when a replacement adds complexity without improving precision.
Definition decision workflow
1. Identify the role
Check whether "psi" is acting as name, noun, symbol in your sentence. A definition is only useful when the grammar matches the way the word is being used.
2. Test the nearest option
Compare it with "greek letter" and other nearby choices to see whether the sentence needs a softer, stronger, or more familiar word.
3. Confirm with context
Use the example sentence below as an evidence check, then read your own sentence out loud to catch tone or rhythm problems.
Review note: Definition pages are checked for source coverage, sentence evidence, synonym support, and editorial insight before they are treated as approval-ready pages. If the evidence is too thin, the page remains available to users but is kept out of the approval-facing indexed inventory.
Final meaning check
Before publishing a sentence with "psi", ask whether the word helps the reader understand the idea faster. A precise word should reduce confusion, not simply make the sentence look more polished.
When the definition, synonym evidence, and example context point in the same direction, the word is usually a safer choice. When they conflict, revise the sentence or choose a clearer alternative.
Definitions
Noun
- 1 The twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek. countable
- 2 Initialism of pre-sentence investigation. abbreviation, alt-of, initialism
- 3 the 23rd letter of the Greek alphabet wordnet
- 4 A form of psychic energy. uncountable
"‘Come, lad,’ he said. ‘We will take tea together and speak of the noumenon, the psi and other more heterogenous phenomena.’"
- 5 Initialism of protein structure initiative. abbreviation, alt-of, initialism
Show 2 more definitions
- 6 a unit of pressure wordnet
- 7 Initialism of pollutant safety/standard index (measurement of the air pollutant such as haze). abbreviation, alt-of, initialism
Symbol
- 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 volts and 60 hertz. The main 450-volt switchboard was energized by the two turbogenerators. The emergency switchboard, in the emergency generator room, was fed from the main switchboard through an electrical tie."
Proper Noun
- 1 Initialism of Policy Studies Institute, a British think tank. UK, abbreviation, alt-of, initialism
Synonyms
All synonymsAntonyms
dimensionless quantitynormal perception
Example
"The recommended tyre pressure of the average car is around 32 psi."
Common questions
What is a synonym for "psi"?
Common synonyms include: greek letter, letter, paranormal ability, pounds per square inch, pressure unit, psychic phenomenon.
How do you use "psi" in a sentence?
The recommended tyre pressure of the average car is around 32 psi.
How do you pronounce "psi"?
Pronounced /psaɪ/.
Etymology
Etymology 1
From Middle English psi, from Latin psī, from Ancient Greek ψεῖ (pseî), the name for the twenty-third letter of the alphabet (Ψ, ψ).
Etymology 2
Initialism of pounds per square inch.