my own definition:
rice is for breakfast, lunch and dinner..hahah
psychological definition:
The term "rice" is humans making their car look more bigger and faster to compensate for their mental and physical problems associated with their social life...

,
thats a little too harsh...
textbook definition:
rice is or are cars that pretend to be fast by using a combination of various techniques to make the observers believe that the car is actually fast, when in reality is not.
whew! that was fun!