To Dominate, be in control of, instruct another in any way you wish. This does not have to include pain, torture, or humiliation but often does. This is where Control is foreplay and the sex that follows is dictated by the Dominator.
S+M: (Sadism and Masicism)
Sadism: Taking Pleasure from Inflicting Pain on others Masicism: Taking Pleasure from Recieving Pain from yourself or others This is where the torture and humiliation is primary, and any sexual pleasure that comes from it is secondary.