The ubiquitous forms of address for women 'Mrs' and 'Miss' are both abbreviations of 'mistress'. Although mistress is a term with a multiplicity of meanings, in early modern England the mistress most commonly designated the female equivalent of master - that is, a person with capital who directed servants or apprentices. Prior to the mid-eighteenth century, there was only Mrs (or Mris, Ms, or other forms of abbreviation), applied to any adult woman who merited the social distinction, without any marital connotation. Miss was reserved for young girls until then. Even when adult single women started to use Miss, Mrs still designated a social or business standing, and not the status of being married, until at least the mid-nineteenth century. This article demonstrates the changes in nomenclature over time, explains why Mrs was never used to accord older single women the same status as a married woman, and argues that the distinctions are important to economic and social historians.