Side Piece

A side piece is usually a person who has an ongoing sexual or romantic relationship with someone who already has a primary partner. The term usually implies a secondary or less prioritized position compared to a main partner, often involving fewer expectations of commitment or exclusivity. In everyday slang the term often carries a slightly objectifying or dismissive tone, framing the person as an accessory to the main relationship. In some kink or D/s contexts, the label may be used deliberately as part of hierarchical or possessive roleplay, where the “side piece” identity becomes part of the dynamic. The term overlaps with concepts like secondary partner, mistress, or affair partner, though it is typically more casual and less formalized. ### Origins of the Term In slang, “piece” has long meant a sexual partner, likely derived from earlier phrases such as “piece of ass." The term appears in Urban Dictionary entries from the early 2000s, where it is defined as a secondary sexual partner outside a main relationship. This suggests the phrase was already common enough in spoken language to be recorded online. During this time, "side piece" became more widely recognized as a way to describe a person someone is seeing on the side.