N. derivative of the verb form 'to rock' which means to be really wicked cool. This meaning is usually demonstrated by raising a balled fist (palm down) to about shoulder height and saying, 'Rock.' This can be applied to any person, place, situation, etc. in which satisfaction is to be expressed.
<1>Dude, Did you just get a free t-shirt!
<2> Yup.
<1> Rock. (gestures)