Ii

[pahy] /paɪ/

noun, plural pis.
1.
the 16th letter of the Greek alphabet (II, π).
2.
the consonant sound represented by this letter.
3.
Mathematics.

/paɪ/
noun (pl) pis
1.
the 16th letter in the Greek alphabet (Π, π), a consonant, transliterated as p
2.
(maths) 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
/paɪ/
noun (pl) pies
1.
a jumbled pile of printer’s type
2.
a jumbled mixture
verb (transitive) pies, piing, pied, pies, pieing, pied
3.
to spill and mix (set type) indiscriminately
4.
to mix up
/paɪ/
adjective
1.
(Brit, slang) short for pious (sense 2), pious (sense 3)
abbreviation
1.
Philippine Islands
2.
private investigator
n.

Greek letter, from Hebrew, literally “little mouth.” As the name of the mathematical constant, from 1841 in English, used in Latin 1748 by Swiss mathematician Leonhart Euler (1707-1783), as an abbreviation of Greek periphereia “periphery.” For the meaning “printer’s term for mixed type,” see pie (3).

pi (pī)
n. pl. pis

Symbol π The 16th letter of the Greek alphabet.

pI (pē’ī’)
n.
The pH value for the isoelectric point of a given substance in solution.
pi
(pī)
An irrational number that has a numerical value of 3.14159265358979… and is represented by the symbol π. It expresses the ratio of the circumference to the diameter of a circle and appears in many mathematical expressions.
pi [(peye)]

The irrational number obtained by dividing the length of the diameter of a circle into its circumference. Pi is approximately 3.1416. The sign for pi is π.

noun

illegal immigrants
Pali
inorganic phosphate
1.
performance indicator
2.
politically incorrect
3.
present illness
4.
primary infertility
5.
principal investigator
6.
private investigator