Word.ws English Dictionary

pi

/paɪ/

pi noun: the sixteenth letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek.

pi: the sixteenth letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek
Image: Mrmw, Public domain, via Wikimedia Commons

Noun (1)

pi (countable and uncountable, plural pis)

  1. The sixteenth letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek.
  2. An irrational and transcendental constant representing the ratio of the circumference of a Euclidean circle to its diameter; approximately 3.14159265.

Noun (2)

pi (countable and uncountable, plural pis)

  1. Metal type that has been spilled, mixed together, or disordered.

Verb

pi (third-person singular simple present pies, present participle piing, simple past and past participle pied)

  1. To spill or mix printing type.

Adjective (1)

pi (not comparable)

  1. Not part of the usual font character set; especially, non-Roman type or symbols as opposed to standard alphanumeric Roman type.
    • In computing, pi characters may be entered with special key combinations.

Noun (3)

pi

  1. pica (conventionally, 12 points = 1 pica, 6 picas = 1 inch).
  2. Piaster.

Adjective (2)

pi

  1. Pious.
    • Our Major was "Cherub" Cheeseman, noted for his foul language. I am afraid he lost a tidy little legacy that he was expecting from his aunt, the Dowager Lady Shuttlecock (a very "pi" old lady), through this same habit of his.1927, Magdalen King-Hall, I Think I Remember: Being the Random Recollections of Sir Wickham Woolicomb, an Ordinary English Snob and Gentleman
    • “Those are very 'pi' sentiments. Was a preacher in Staffordshire— I was raised chapel, though've tried to forget it—he talked that way... redemption and the lot.”1972, Anya Seton, Green Darkness, Hachette UK, →ISBN

Proper noun (1) capitalized: PI

PI

  1. (abbreviation) Abbreviation of Piauí: a state of Brazil.
  2. (abbreviation, initialism) Initialism of Prison Industries, the prison-run work program for inmates.
  3. (Philippines, US, abbreviation, dated, historical, initialism) Initialism of Philippine Islands.
    • We're going back to the PI for a vacation this summer.
    Synonyms:
    PH, PHL, PHI

Adjective (3) capitalized: PI

PI (comparative more PI, superlative most PI)

  1. (abbreviation, initialism) Initialism of politically incorrect (see PC).

Noun (4) capitalized: PI

PI (countable and uncountable, plural PIs)

  1. (abbreviation, initialism) Initialism of processing instruction.
  2. (abbreviation, initialism) Initialism of partial induction (see AI).
  3. (abbreviation, initialism) Initialism of personal injury.
  4. (abbreviation, initialism) Initialism of principal investigator (“lead researcher on a grant-funded project”).
  5. (abbreviation, initialism) Initialism of private investigator.
  6. (abbreviation, initialism) Initialism of parallel import.
  7. (abbreviation) Abbreviation of phosphatidylinositol, a phospholipid component of eukaryotic cell membranes, also abbreviated in PtdIns.
  8. (abbreviation, initialism) Initialism of protease inhibitor.
  9. (abbreviation, initialism) Initialism of polyimide.
  10. (abbreviation, initialism) Initialism of ponderal index.
  11. (abbreviation, initialism) Initialism of penile inversion.
  12. (abbreviation, initialism) Initialism of power integrity.
Show 7 more meaningsShow fewer meanings
  1. (abbreviation) Abbreviation of prohibited immigrant.
  2. (abbreviation, initialism, slang) Initialism of pseudoincest.
  3. (abbreviation, initialism) Initialism of port injection (“fuel injection”).
  4. (abbreviation, initialism) Initialism of paradoxical intention.
  5. (abbreviation, initialism) Initialism of pro forma invoice.
  6. (Philippines, abbreviation, initialism) Initialism of people's initiative.
  7. (abbreviation, initialism) Initialism of preliminary injunction.

Proper noun (2) capitalized: Pi

Pi

  1. (historical) A county of Chengdu, Sichuan, China.
    • Pi County has brought democracy into full play. The peasants there are electing production team leaders and other production team cadres by secret ballot.1978 November 27 [1978 November 19], “Szechwan Peasants Elect Production Team Leader By Secret Ballot”, in Daily Report: People's Republic of China, volume I, number 228, Foreign Broadcast...
    • [...]water carriers, the sedanchair carriers, the pawn brokers, and even the manure collectors in a market town in Pi county, Szechwan in the late Ch'ing period.1983, Cheng-yün Liu, The Ko-lao Hui in Late Imperial China, →OCLC, page 133

pi meaning in Hindi, Tamil, Marathi and Urdu

pi in Hindi

letter of Greek alphabet
पाइ pāi
irrational mathematical constant
पाइ pāi

pi in Tamil

பி. ஐ, பிஐ

pi in Marathi

पाई

pi in Urdu

پائی, پی آئی
More languagesFewer languages
pi in Telugu
పి. ఐ, పిఐ
pi in Malayalam
പി. ഐ, പൈ, പിഐ
pi in Kannada
ಪೈ pai
pi in Punjabi
ਪੀ. ਆਈ
pi in Gujarati
પાઇ pāi
pi in Odia
ପି. ଆଇ, ପିଆଇ
pi in Nepali
पाई, पाइ
pi in Arabic
بِي bī, پِي pī, ط ṭāʔ, بَاي bāi
pi in Malay
pi
pi in Persian
پی pi
Sindhi
پاءِ pāi

Examples of pi in a sentence

  • The exact value of pi cannot be represented in decimal notation.
  • I approximated the value of pi by taking 22 divided by 7.
  • Zero, one, −1, 2.5, and pi are all numbers.

All 36 example sentences with pi

Synonyms of pi

1 more synonymsFewer synonyms

Forms of pi

Noun
pluralpis
pluralPIs
Verb
third-person singular presentpies
present participlepiing
past participlepied
pastpied
Proper noun
alternative formP.I.
alternative formP. I.
alternative formPe
alternative formP'i
Adjective
comparativemore PI
superlativemost PI

Plural of pi: pis

Origin of pi

From Koine Greek πῖ (pî), from Ancient Greek πεῖ (peî), ultimately from Proto-Semitic *pay- (“mouth”). Doublet of pe. Its mathematical use apparently stems from its use as the first letter in περιφέρεια (periphéreia, “periphery; circumference”) and was first cited in 1706 in the Synopsis Palmariorum Matheseos by William Jones.

Unclear. Possibly from the Greek letter (see Etymology 1) as a common example of non-alphabetic character, possibly from pica (“type size”) (see Etymology 3), possibly from pie referring to its mixed nature or pied (“checkered, multicoloured”).

Abbreviations.

Words formed from pi

Phrases with pi

Words that rhyme with pi

48 more rhymesFewer rhymes

Questions about pi

What does pi mean?
Pi means the sixteenth letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek.
What is pi in Hindi?
Pi in Hindi is पाइ (pāi). See Pi meaning in Hindi.
What part of speech is pi?
Pi can be a noun, a verb, an adjective or a proper noun.
How do you pronounce pi?
Pi is pronounced /paɪ/.
What is the plural of pi?
The plural of pi is pis.

Words near pi in the dictionary

  1. phœtal
  2. phœti
  3. phœtus
  4. phœtuses
  5. phở
  6. pi
  7. pi bond
  8. pi bonds
  9. pi character
  10. pi characters
  11. Pi Day

Source and license

Adapted from Wiktionary: pi (page history and authors); PI (page history and authors); Pi (page history and authors); pi (Tamil, IndicTrans2 machine translation) (model and license); pi (Marathi, IndicTrans2 machine translation) (model and license); pi (Urdu, IndicTrans2 machine translation) (model and license); pi (Telugu, IndicTrans2 machine translation) (model and license); pi (Malayalam, IndicTrans2 machine translation) (model and license); pi (Punjabi, IndicTrans2 machine translation) (model and license); pi (Odia, IndicTrans2 machine translation) (model and license); pi (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-pi.ogg.

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