Lay people are increasingly invited to deliberate on emerging technologies in public engagement settings. Analogies appear frequently in these contexts and are commonly understood as means of making sense of and forming an opinion on emerging technologies. This article provides an alternative perspective, which conceptualizes analogies as rhetorical devices employed to achieve specific functions. A repertoire of rhetorical roles is traced in four public engagement settings on nanotechnology: (1) analogies suggesting acceptance/rejection of specific nano-applications, (2) anticipatory and alerting analogies constructed to plausibilize and prevent futures, (3) killer analogies closing debate and arguments, and (4) "nano is not like nano" moves that distinguish between application domains. Each role points to specific dimensions and tensions of public engagement processes. Overall, the findings reveal that lay people use analogies to make arguments and enforce framings rather than to just make sense of nanotechnology, which refutes the assumption of a public opinion deficit.