Basic Rock Concepts
"The road", freedom and spontanity. Everything started with the novel "On the Road" by Jack Kerouac, then you have "Easy Rider" and other road movies, not to mention songs.
"The edge" is most often used in two meanings:
1. extremes, deep and intense feelings in life;
2. the border of the ordinary state of conscience, which can be perceived during near-death/out-of-body/spiritual/psychedelic experience.
It's the way of life - take it all as it comes, seize the day, with nothing to lose and to regret (but often without direction and goal as well). This term gave birth to The Rolling Stones band name, Rolling Stone magazine etc.
Songs stem from "Rollin' Stone" by Muddy Waters.
Rock songs often deal with the highest level of generalization, reflections on life-and-death subjects. From meditative psychedelia to epic progressive compositions.
Songs of freethinking nature, dystopia, political sarcasm, pacifism etc.