Market research has developed a precise vocabulary over decades of applied practice, academic refinement, and methodological debate. The terms below represent the working language of the discipline — used by brand strategists, consumer insight teams, product developers, and policy researchers. Definitions are given in their professional sense, not their colloquial approximations. A/B Testing A controlled experiment in which two versions of a stimulus — an advertisement, a product page, a pricing structure, a survey question — are exposed to separate audience segments simultaneously.