The words and metaphors that people use to describe sexuality and reproductive health reflect experiences with peers, sexual partners, health service providers, and public health campaigns. In this paper, we analyse 1,134 e-mails sent to an emergency contraception website in the USA over the course of a one year period. Through an examination of the terminology used by authors to describe contraceptive methods, sexual intercourse and other sexual acts, we analyse what those terms signify within their textual context. We find that the kinds of risk concerns used in assessing sexual activity – whether evaluating pregnancy risk, disease transmission risk, or moral risk – influence the definitions people give to terms that are multiply defined or whose definitions are culturally contested. This finding emerged clearly in the meanings given to terms for “sex” and “unprotected sex,” which varied widely. We conclude with a discussion of the implications of this finding for research, clinical care, and health education activities.