Definition of Hip Hop

I found this video on one the hip hop sites that I visit daily and it brought up an idea that I think about to myself from time to time. What is hip hop? For someone like myself to state that some of the things that we are exposed to be consider NOT be hip hop there must be some kind of definition of what it is. As you will see in the video the many artists and individuals in the video have trouble providing a definition. I understand that hip hop is very complex and a broad encompassing culture but that's why I think the definition is easy to state but hard to comprehend. Hip hop - n. (proper) the "creative" self-expression of an individual and/or group of people that include some form or combination of the four main "elements" of hip hop culture: MCing (rapping), DJing, urban inspired art/tagging (graffiti), and b-boying (or breakdancing). Our culture has evolved overtime but if it remains honest and "creative" thats "hip hop" to me.... What do you think? Leave a comment....