Originally defined as the ratio between the circumference of a circle and its diameter, pi — written as the Greek letter π — appears throughout mathematics, including in areas that are completely unconnected to circles such as chemistry,

Pi, which is the ratio of a circle's circumference to its diameter, is celebrated with its own holiday on March 14.

Pi Day, March 14th, when the date reads 3.14, might just be one of my favorite national food days. Personally, I'm not a "math person," but I am a baker who is never going to pass up an opportunity to celebrate with pie.