BDSM is bondage, discipline (or domination), sadism, and masochism.

BDSM is an umbrella term encompassing a variety of erotic practices.

Bondage and Discipline involves the use of physical restraints.

Dominance and Submission involves one partner taking on a controlling to the dominant partner.

Sadism and Masochism involves deriving pleasure from inflicting pain,

masochism involves deriving pleasure from receiving pain.

At its core, BDSM is about exploring power dynamics, trust, and sexual expression.