Bodybuilding in its most general sense means you are building muscle. But in a more professional sense, if you are a bodybuilder, you are doing a lot more than working out. You are eating in the correct way to build muscle, taking supplements, and monitering your overall health. In effect, you are maximizing your muscle building limits. Those that work out are in to weight lifting. They are not bodybuilders. You become a bodybuilder when you are training for competitions and/or you make lifting your life.
IF you're working out 3x per week after work/ class and you want to build muscle, you are not a bodybuilder.
If you get up, eat bfast, 3 hrs later eat chicken, 2 hrs later eat a protein bar, 3 hrs later eat a breast of chicken and your flax seed oil, 2 hrs later take your creatine, protein shake, and other supplement, then you go to the gym, then come back and eat pasta and some chicken, only to take another protein shake, and go to bed. Now you are a bodybuilder. BIG DIFFERENCE.
Some of you will disagree with this statement, but its my opinion. And I have a feeling a lot of guys that are 'bodybuilders' don't want the word to be thrown around like its nothing.