Prior work suggests that some cisgender people do not consider gender identity when thinking about what being transgender means, and that exposure to a definition of transgender can reduce negative attitudes toward transgender people. In two studies, we sought to integrate these lines of research by examining whether anti-transgender attitudes are associated with how cisgender people define the term transgender. In Study 1, 293 participants (132 female and 157 male; four participants did not report their sex/gender) recruited via Mechanical Turk were randomly assigned to one of two conditions. Participants in one condition first read a definition of "transgender" that referred to gender identity and then reported their attitudes toward transgender people. Participants in the other condition did not read the definition and instead simply reported their attitudes toward transgender people. Contrary to predictions, exposure (vs. lack thereof) to the definition did not affect attitudes. However, participants who identified gender identity as a central component of the definition of transgender on a manipulation check endorsed more positive attitudes. In Study 2, 295 cisgender participants (165 women and 130 men; recruited via Mechanical Turk) wrote down their own definitions of transgender. Participants who spontaneously included (vs. did not include) gender identity in their definitions reported distinctively positive attitudes. Observed effects held over and above individual differences in cognitive style, gender identification, contact with transgender people, and participant gender.How cisgender people think about gender identity may thus index their attitudes toward transgender people.