I don't know why i am asking that but I realy need to know what Udacity stands for
This was answered here - what-does-the-word-udacity-mean
"Udacity" originates from "audacious".
"Audacious" then stands for something that is fearless and courageous, something that is daring or bold. We could assume that it refers to the project itself which is courageous through it's goals : which appear to be : providing quality education to masses for free with the help of modern technologies.
According to Sebastian Thrun (co-founder of Udacity) :