The purpose of the study was to examine adolescent perceptions of the terms abstinence and sexual activity and also to determine if age, gender, virginity status, attendance at religious services, and perceived religiosity were associated with any particular perception of these terms. Current federal efforts to prevent teen pregnancy have emphasized abstinence education. The legislation that authorizes funding for these programs requires that educators teach students that they should abstain from sexual activity until marriage. The terms abstinence and sexual activity, however, are not defined. Participants in this study (311 students in grades 7–12 in a southern, rural school district) completed a questionnaire that included two open-ended questions asking them to define the terms abstinence and sexual activity. The most frequent definition of sexual activity (34.4%) identified it as “having,” “participating,” or “engaging” in “sex.” Thus, the definitions given by students were not more precise than the terms they were asked to define. Analyses (chi-square) that examined the independence of age, gender, virginity status, attendance at religious services, and perceived religiosity with perceptions of abstinence or sexual activity found only age and perception of abstinence to be statistically significant. These findings have implications for programs that encourage young people to abstain from sexual activity.