Kungfu is believed by many to predate recorded history so it is not widely known when it originated there are many names to describe chinese martial arts such as Kuo-shu,Wu Shu,Tao-fa,
Hundreds of different fighting styles is what kung fu is based on as opposed to just one fighting style which is what most mistakenly believe when referring to the term kungfu a compilation of several different fighting styles is how kungfu can be described or defined when most seee a practitioner of the art form in action the automatically assume that the practitioner is practicing kungfu as opposed to a specific style of kungfu.
Many forms of fighting is how it can be defined all created by different observations but most or all of the styles incorporate the same basic kungfu fighting principles which are grappling, kicking,punching, throwing, etc these all makeup the primary categories or areas of kungfu, almost every form of kungfu is based around these four principles or techniques.
To properly apply what is taught is as important as learning the art itself if you take away the history of martial arts or any other art form the question needs to be asked what are you really learning?, in this respect the study of martial arts is no different than any other art form, to properly apply what is being taught is very impotant in mastering the particular art form itself.
So Kung Fu is not the description of one style of fighting but many forms of fighting, it is a collective of many forms of fighting styles all based around different observations but all the styles incorporate the same basic Kung Fu fighting principles which are seizing and locking, striking, kicking, throwing and grappling, are the four primary areas or categories of Kung Fu almost every form of kung fu is based around these techniques.