Gonna have to go two-for-two on correcting replies here.
> FM is Frequency Modulation which is what you can do with oscillators and the above mentioned envelope points.
This isn't what FM is. FM involves using one oscillator output to modify (modulate) the frequency of another oscillator. ADSRs can be used to shape the degree of modulation over time, but the sound isn't shaped through the ADSR in this case; rather the ADSR controls the sound generation stage by modifying the frequency modulation effect in the time domain.