Pi may refer to any of the following:
1. The mathematical constant pi (the Greek lowercase letter π) is equal to the ratio of a circle's circumference to its diameter. It is an irrational number, whose value to twenty-four digits is 3.14159265358979323846264.
To insert the pi symbol in a web page, use the extended HTML code π.
The unofficial Pi day is celebrated March 14th of every year, which is 3/14 or the first three digits of pi.
In Windows, to insert a pi symbol, open the character map tool. Select and copy the mark to be inserted into any document or picture.
2. Pi is also the symbol for a Pebi.