Pi

//paɪ// adj, name, noun, verb

Definitions

Adjective
  1. 1
    Not part of the usual font character set; especially, non-Roman type or symbols as opposed to standard alphanumeric Roman type. not-comparable

    "In computing, pi characters may be entered with special key combinations."

  2. 2
    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."

Proper Noun
  1. 1
    Abbreviation of Piauí: a state of Brazil. abbreviation, alt-of
  2. 2
    A county of Chengdu, Sichuan, China. historical

    "Pi County has brought democracy into full play. The peasants there are electing production team leaders and other production team cadres by secret ballot."

  3. 3
    Initialism of Prison Industries, the prison-run work program for inmates. abbreviation, alt-of, initialism
  4. 4
    Initialism of Philippine Islands. Philippines, US, abbreviation, alt-of, dated, historical, initialism

    "We're going back to the PI for a vacation this summer."

Noun
  1. 1
    The sixteenth letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek. countable, uncountable
  2. 2
    Metal type that has been spilled, mixed together, or disordered. countable, uncountable
  3. 3
    pica (conventionally, 12 points = 1 pica, 6 picas = 1 inch).
  4. 4
    Initialism of processing instruction. abbreviation, alt-of, countable, initialism, uncountable
  5. 5
    an antiviral drug used against HIV; interrupts HIV replication by binding and blocking HIV protease; often used in combination with other drugs wordnet
Show 24 more definitions
  1. 6
    An irrational and transcendental constant representing the ratio of the circumference of a Euclidean circle to its diameter; approximately 3.14159265358979323846264338327950; usually written π. countable, uncountable
  2. 7
    Piaster.
  3. 8
    Initialism of partial induction (see AI). abbreviation, alt-of, countable, initialism, uncountable
  4. 9
    the 16th letter of the Greek alphabet wordnet
  5. 10
    Initialism of personal injury. abbreviation, alt-of, countable, initialism, uncountable
  6. 11
    the scientist in charge of an experiment or research project wordnet
  7. 12
    Initialism of politically incorrect (see PC). abbreviation, alt-of, countable, initialism, uncountable
  8. 13
    someone who can be employed as a detective to collect information and assist in criminal investigations wordnet
  9. 14
    Initialism of principal investigator (“lead researcher on a grant-funded project”). abbreviation, alt-of, countable, initialism, uncountable
  10. 15
    the ratio of the circumference to the diameter of a circle; approximately equal to 3.14159265358979323846 … wordnet
  11. 16
    Initialism of private investigator. abbreviation, alt-of, countable, initialism, uncountable
  12. 17
    Initialism of parallel import. abbreviation, alt-of, countable, initialism, uncountable
  13. 18
    Abbreviation of phosphatidylinositol, a phospholipid component of eukaryotic cell membranes, also abbreviated in PtdIns. abbreviation, alt-of, countable, uncountable
  14. 19
    Initialism of protease inhibitor. abbreviation, alt-of, countable, initialism, uncountable
  15. 20
    Initialism of polyimide. abbreviation, alt-of, countable, initialism, uncountable
  16. 21
    Initialism of ponderal index. abbreviation, alt-of, countable, initialism, uncountable
  17. 22
    Initialism of penile inversion. abbreviation, alt-of, countable, initialism, uncountable
  18. 23
    Initialism of power integrity. abbreviation, alt-of, countable, initialism, uncountable
  19. 24
    Abbreviation of prohibited immigrant. abbreviation, alt-of, countable, uncountable
  20. 25
    Initialism of pseudoincest. abbreviation, alt-of, countable, initialism, uncountable
  21. 26
    Initialism of port injection (“fuel injection”). abbreviation, alt-of, countable, initialism, uncountable
  22. 27
    Initialism of paradoxical intention. abbreviation, alt-of, countable, initialism, uncountable
  23. 28
    Initialism of pro forma invoice. abbreviation, alt-of, countable, initialism, uncountable
  24. 29
    Initialism of People's Initiative. Philippines, abbreviation, alt-of, countable, initialism, uncountable
Verb
  1. 1
    To spill or mix printing type.

Etymology

Etymology 1

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.

Etymology 2

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”).

Etymology 3

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”).

Etymology 4

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”).

Etymology 5

Abbreviations.

Etymology 6

Abbreviations.

Etymology 7

From Mandarin 郫 (Pí).

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