x^2 is quadratic, 2^x (for example) is exponential. Have a look at http://en.wikipedia.org/wiki/Time_complexity http://en.wikipedia.org/wiki/Time_complexity ,

x^2 is quadratic, 2^x (for example) is exponential. Have a look at http://en.wikipedia.org/wiki/Time_complexity http://en.wikipedia.org/wiki/Time_complexity , it's pretty comprehensive.