This review explores usage of the term public in debates about science and society. Since the 1980s, there has been a broad shift from public understanding and science communication towards engagement, dialogue and participation. I explore the multiple meanings of public in these debates, including the transition from singular the public to plural publics; the importance of imagined publics; the implications of science in public; and of the public interest. Academics and communicators from any field can benefit from thinking through public(s) in this way – therefore I close with some suggestions for changing research practice that flow from these ideas.