The phrase "rhythm of something" refers to the regular, repeated pattern or flow that characterizes a particular activity, event, or process. It is the natural movement or beat that occurs in music, dance, poetry, speech, or any other form of expression or performance. The rhythm can be described as the timing and arrangement of sounds or movements, which creates an overall feeling or mood for the listener or viewer. In essence, it's what makes something feel "in sync" or "flowing smoothly."