Nature-based early childhood education. Nature-based preschool. Nature preschool. Forest kindergarten. Nature kindergarten. Waldkindergarten. Forest school. These are a few of the program terms currently being discussed among early childhood environmental education professionals in the United States. Why is there so much discussion about the names now? Do the names mean the same thing? Why should early childhood environmental educators be concerned about defining the similarities and differences among these programs? The paper focuses in answering these questions, and also in reflecting what can be learned from other program definitions to enhance the current definition of nature-based preschools.