BackgroundThe scientific term for the substance people inhale and exhale from a vaping device is ‘aerosol’, but whether the public uses this term is unclear. To inform tobacco control communication efforts, we sought to understand what tobacco users call e-cigarette aerosols.MethodsParticipants were a national convenience sample of 1628 US adults who used e-cigarettes, cigarettes or both (dual users). In an online survey, conducted in spring 2021, participants described what ‘people inhale and exhale when they vape’, using an open-ended and then a closed-ended response scale. Participants then evaluated warning statements, randomly assigned to contain the term ‘aerosol’ or ‘vapor‘ (eg, ‘E-cigarette aerosol/vapor contains nicotine, which can lead to seizures’).ResultsIn open-ended responses, tobacco users most commonly provided the terms ‘vapor’ (31%) and ‘smoke’ (23%) but rarely ‘aerosol’ (pp>0.05).ConclusionsThe public rarely uses the term ‘aerosol’ to describe e-cigarette output, potentially complicating educational efforts that use the term. Future studies should explore public knowledge and understanding of the terms ‘aerosol’ and the more popular ‘vapor’ to better inform vaping risk communication.