Definition of 'pi'
number
Pi is a number, approximately 3.142, which is equal to the distance round a circle divided by its width. It is usually represented by the Greek letter π.
Pi is thought to have made about 15 times its outlay.
Collins COBUILD Advanced Learner’s Dictionary. Copyright © HarperCollins Publishers
Word Frequency
pi in British English 1
nounWord forms: plural pis
2. mathematics
a transcendental number, fundamental to mathematics, that is the ratio of the circumference of a circle to its diameter. Approximate value: 3.141 592…; symbol: π
Collins English Dictionary. Copyright © HarperCollins Publishers
Word origin
C18 (mathematical use): representing the first letter of Greek periphereia peripheryWord Frequency
pi in British English 2
verbWord forms: pies, piing, pied or pies, pieing, pied (transitive)
4.
to mix up
Collins English Dictionary. Copyright © HarperCollins Publishers
Word origin
C17: of uncertain origin
Word Frequency
pi in British English 3
adjective
Collins English Dictionary. Copyright © HarperCollins Publishers
Word Frequency
PI in British English
Collins English Dictionary. Copyright © HarperCollins Publishers
Word Frequency
PI in American English
Slang
private investigator
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word Frequency
pi in American English 1
nounWord forms: plural pies
1.
2.
any jumble or mixture
verb transitiveWord forms: pied, ˈpieing or ˈpiing
3.
to make jumbled; mix up (type)
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin
see pie2Word Frequency
pi in American English 2
noun
1.
the sixteenth letter of the Greek alphabet (Π, π)
2.
a.
the symbol (π) designating the ratio of the circumference of a circle to its diameter
b.
the ratio itself, equal to 3.14159265+: often approximated as 22⁄7
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin
Gr pi, earlier pei < Sem, as in Heb pēWord Frequency
pi in American English 1
(pai)
nounWord forms: plural pis
1.
the 16th letter of the Greek alphabet (II, π)
2.
the consonant sound represented by this letter
3. Math
a.
the letter π, used as the symbol for the ratio of the circumference of a circle to
its diameter
b.
the ratio itself: 3.141592+
Most material © 2005, 1997, 1991 by Penguin Random House LLC. Modified entries © 2019
by Penguin Random House LLC and HarperCollins Publishers Ltd
Word origin
[1835–45; ‹ Gk pî, peî; used in mathematics to represent Gk periphérion periphery]Word Frequency
pi in American English 2
(pai) (noun plural pies, verb pied, piing)
Also: pie
Most material © 2005, 1997, 1991 by Penguin Random House LLC. Modified entries © 2019
by Penguin Random House LLC and HarperCollins Publishers Ltd
Word origin
[1650–60; orig. uncert.]Word Frequency
Pi. in American English
piaster
Also: piMost material © 2005, 1997, 1991 by Penguin Random House LLC. Modified entries © 2019
by Penguin Random House LLC and HarperCollins Publishers Ltd
Word Frequency
P.I. in American English
abbreviation
1.
Philippine Islands
2. Also: p.i.
private investigator
Most material © 2005, 1997, 1991 by Penguin Random House LLC. Modified entries © 2019
by Penguin Random House LLC and HarperCollins Publishers Ltd
pi
GreekQuick word challenge
Quiz Review
Question: 1
-
Score: 0 / 5
Which letter of the Greek alphabet am I?
the 18th letter in the Greek alphabet (Σ, σ, or, when final, ς), a consonant, transliterated as S
Which letter of the Greek alphabet am I?
the eighth letter of the Greek alphabet (Θ, θ), a consonant, transliterated as th
Which letter of the Greek alphabet am I?
the 20th letter in the Greek alphabet (Υ, υ), a vowel, transliterated as y or u
Which letter of the Greek alphabet am I?
the fourth letter in the Greek alphabet (Δ, δ), a consonant transliterated as d
Which letter of the Greek alphabet am I?
the 16th letter in the Greek alphabet (Π, π), a consonant, transliterated as p
Your score:
Examples of 'pi' in a sentence
pi
Example sentences from the Collins Corpus
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"" I took an option out on pi meson production, the kind that are made of a down and
anti-up quark pair.
A computer scientist claims to have calculated pi to nearly 2,700 billion digits,
some 123 billion more than the previous record, using a desktop computer.
Is there a non-decimal base - binary, octal, base 7 - in which the value of pi can
be expressed precisely?
Pi is a physical constant defined as the ratio of a circle 's circumference to its
diameter.
Pi limitation leads to dephosphorylation of adenosine monophosphate and the allosteric
activator of isocitrate dehydrogenase key to lipid biosynthesis.
Pi, the ratio of a circle's circumference to its diameter, is an irrational number,
containing an infinite number of digits.
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Definition of pi from the Collins English Dictionary
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