A type of music ussually simple, ussually blasting policital influenced songs that have been watered down in the 90's, but not killed. punk rock has pre existed its actual definition, as it is an expression musically agianst a government that would step on the people. many people believe that punk rock can only be 3 chords and simple lyrics as the last definition stated, which is very over stereotyped and false. Thier are many forms of punk including crust punk, hardcore, screamo and so forth, pop punk is not punk in any way.
real punk rock is not confined to over simplistic chords and lyrics but can have talented musicians (ie. the dead kennedys, DOA, SNFU, pennywise)