pi
PY/paɪ/
Pluralpis
Pluralpis
- 1A number, about 3.14, found by dividing the distance around a circle by the distance across it.
Our teacher showed us how to use pi to find the distance around a bike wheel.
Some students try to remember pi to dozens of digits.
Note
- 2The 16th letter of the Greek alphabet. In an older Greek alphabet, it was the 17th.
His club sweatshirt has the Greek letters alpha and pi on the front.
In Greek class, we practiced writing a capital pi until it looked neat.
Note
- 3A short way to write pica, a unit for measuring printed type. Six picas make one inch.
- 4Metal letters for printing that have been dropped or mixed up into a mess.
- 5To drop or mix up the metal letters used for printing.
- 6Describes special symbols that are not part of the normal letters and numbers in a font.
- 7A short form of piaster, a unit of money.
- 8Very religious, or very serious about being good.
“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
Showing meanings only.
Practice
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Origin
It comes from a Greek letter. Its use in maths seems to come from the Greek word for "circumference", which starts with this letter.
Checked 1 Nov 2026 · 2 facts
- Pi comes from the name of a Greek letter. en.wiktionary.org
- Its mathematical use apparently derives from the initial letter of the Greek word for circumference. en.wiktionary.org