Friends:

   The 3 domains of the Noble 8-Fold Way:

A former husband of a Buddhist Nun (=Bhikkhuni) once asked her:
Venerable Dhammadinna, are these 3 domains  of morality (sīla),
concentration (samādhi), and understanding (pañña) included in the
Noble 8-fold Way, or is it rather instead the Noble 8-fold Way
that is included & divided into the 3 core domains of the training?
The 3 domains, Visākha, are not included in the Noble 8-fold Way,
but the Noble 8-fold Way is included in those 3 domains like this:
Right speech, right action, and right livelihood: These 3 things are
included in the domain of morality...
Right effort, right awareness, and right concentration: These things
are included in the domain of concentration...
Right view and right motivation: These things are included in the
domain of understanding.