pi
Pronunciation[change]
Noun[change]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/42/Greek_lc_pi.svg/220px-Greek_lc_pi.svg.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/2a/Pi-unrolled-720.gif/220px-Pi-unrolled-720.gif)
- Pi is a Greek letter written "π".
- (mathematics) Pi is a number that is found by dividing the circumference of a circle by its diameter. Pi is constant, it is always the same (close to 3.14159 , also accurate approx as , or rough approx as ). It is usually written as "π"
- The distance around a circle is twice the radius times pi; C = 2πr.