First Known Use: 1638
Dictionary
1pi
noun \ˈpī\
plural pis \ˈpīz\
Definition of PI
1
: the 16th letter of the Greek alphabet — see alphabet table
2
a : the symbol π denoting the ratio of the circumference of a circle to its diameter b : the ratio itself : a transcendental number having a value rounded to eight decimal places of 3.14159265
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Origin of PI
Middle Greek, from Greek pei, of Semitic origin; akin to Hebrew pē pe
2pi
noun \ˈpī\
plural pies
Definition of PI
1
: type that is spilled or mixed
2
: a pi character or matrix
Variants of PI
pi also pie \ˈpī\
Origin of PI
origin unknown
First Known Use: circa 1659
3pi
verb
piedpi·ing or pie·ing
Definition of PI
transitive verb
: to spill or throw (type or type matter) into disorder
intransitive verb
: to become pied
Variants of PI
pi also pie
First Known Use of PI
1889
4pi
adjective
Definition of PI
1
: not intended to appear in final printing <pi lines>
2
: capable of being inserted only by hand <pi characters>
Variants of PI
pi also pie
First Known Use of PI
circa 1940
PI
abbreviation
Definition of PI
1
Philippine Islands
2
private investigator
3
programmed instruction
See PI defined for English-language learners
PI[1] Defined for Kids
pi
noun \ˈpī\
plural pis \ˈpīz\
Definition of PI for Kids
1
: the symbol π representing the ratio of the circumference of a circle to its diameter
2
: the ratio itself having a value of about 3.1416
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