The Guinness World Record for the most memorized digits of pi is held by Rajveer Meena, for memorizing 70,000 decimal places of the mathematic concept. The Guinness World Record for the world’s largest pie is 20 feet across and weighs 3,699 pounds. The highest anyone in the DBH staff can count to Pi is only seven digits. And National Pi Day, March 14, was declared a holiday in 2009 by the U.S. House of Representatives.
So, what is Pi? Other than the 16th letter of the Greek alphabet, Pi is a mathematical concept that represents the ratio of a circle's circumference to its diameter and astrological reference. Today, 3/14, symbolizes Pi day on the Gregorian calendar.
pi
pī/
noun
noun: pi; plural noun: pis

1.
the sixteenth letter of the Greek alphabet ( Π, π ), transliterated as ‘p.’

the numerical value of the ratio of the circumference of a circle to its diameter (approximately 3.14159).

ASTRONOMY
the sixteenth star in a constellation.
noun: Pi
"Pi Herculis" 
CHEMISTRYPHYSICS
relating to or denoting an electron or orbital with one unit of angular momentum about an internuclear axis.
modifier noun: pi

symbol
symbol: π; symbol: Π; symbol: pi

1.
the numerical value of pi.

osmotic pressure.

mathematical product.
