Defining privacy requires a familiarity with its ordinary usage, of course, but this is not enough since our common ways of talking and using language are riddled with inconsistencies, ambiguities, and paradoxes. What we need is a definition which is by and large consistent with ordinary language, so that capable speakers of English will not be genuinely surprised that the term “privacy” should be defined in this way, but which also enables us to talk consistently, clearly, and precisely about the family of concepts to which privacy belongs. Moreover the definition must not usurp or encroach upon the basic meanings and functions of the other concepts within this family. Drawing useful and legitimate distinctions between different values is the best antidote to exploitation and evisceration of the concept of privacy.