BDSM is a compound acronym derived from the terms bondage and discipline (B&D, B/D, or BD), dominance and submission (D&s, D/s, or Ds), sadism and masochism (S&M, S/M, or SM).

BDSM includes a wide spectrum of activities, forms of interpersonal relationships, and distinct subcultures. While not always overtly sexual in nature, the activities and relationships within a BDSM context are almost always eroticized by the participants in some fashion. Many of these practices fall outside of conventional sexual activities and human relationships.

Activities and relationships within a BDSM context are characterized by the fact that the participants usually take on complementary, but unequal, roles. Typically, participants who are active — applying the activity or exercising control over others — are known as tops or Dominants. Those participants who are recipients of the activities, or who are controlled by their partners, are typically known as bottoms or submissives. Individuals who move between top/dominant roles and bottom/submissive roles—either periodically within a relationship, or from relationship to relationship—are known as S/switches.