# What does integrating a function wrt to another function intuitively mean? [duplicate]

I sometimes see stuff that is of the following notation:

$$\int f(x) dG(x)$$

I reckon a specific example would be:

$$\int x \operatorname{d \sin(x)}$$

How can one intuitively interpret this. Does this mean that we're compressing and stretching the x-axis by a sin function?