What is the definition of "pop culture"?

In my eyes, pop culture is a source of entertainment that appeals to the majority of a society, focusing mainly on the "trendsetters", which include teenagers and young adults. For example, Lady Gaga is one of the most popularly music artists of today. She has millions of fans around the world for her outrageous fashion statements and original songs. On television, the show, Breaking Bad, has become a new hit sensation throughout the country. In addition, the movie industry recently released, Iron Man 3, which had one of the highest grossing rates this year. These popular forms of entertainment tend to appeal more to a younger crowd, however, they are the most talked about hit sensations. Pop culture is definitely seen through trends of the younger generations and will continue to be seen like that.