Top Definition
The penis identity is a mathematical equation, or identity: 8=D. The identity is similar to others, such as Euler's identity, in that it uses constants rather than variables. It is occasionally written with multiple "=" for emphasis.
Instead of writing down formulas on my chemistry cheat sheet, I just wrote the penis identity: 8=====D.
by Jario777 February 03, 2011

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.