What's the difference between a weightlifter and a powerlifter?
A weightlifter does not employ absolute strength, where a powerlifter does...
because his competition lifts allows him that freedom.
The above quick answer is only part of a more comprehensive answer. If someone was to come up to me when I was weightlifting and give me the answer I've just give here, I may have had a reason to object. Which leads me to further clarify my answer.
Everyone would agree that the main goal in both sports would be to lift as much weight as possible. However due to the nature of the Olympic lifts, namely the clean & jerk, and snatch, a weightlifter is prohibited from employing his absolute strength as a powerlifter would be able to.
A clean (for example), is two lifts combined to make one,... namely the pull and the front squat. Had the weightlifter broke the clean into its different components he, (like the powewrlifter), would be in a better and more suitable position to employ more force into those lifts, hence bringing him closer to achieving his absolute strength as would be achievable by a powerlifter.
Example: A weightlifter who can pull (say) 180kg, and front squat 200kg, may only be able to clean 165kg.
Example: A powerlifter who can dead lift 250kg and back squat 300kg, can dead lift 250kg and back squat 300kg! His sport allows him more room to fulfil his absolute strength.
Fadi.