There is no agreed definition of lean construction. This is a problem for some and not for others in the lean construction community and beyond. Answers to the question 'what is lean construction?'' from a simple survey reported here, on the web and in the formal and informal literature reveal a diversity of views. The purpose of the survey was to get a sense of the definitions-in-use in the lean construction community. Some of the implications for the community are outlined and suggestions made for further study.